Class 10

Punjab State Board PSEB 10th Class Maths Book Solutions Chapter 5 Arithmetic Progressions Ex 5.1 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Maths Chapter 5 Arithmetic Progressions Ex 5.1

Question 1.
In which of the following situations, does the list of numbers involved make an arithmetic progression, and why ?
(i) The taxi fare after each km when the fare is 15 for the first km and 8 for each additional km.

(ii) The amount of air present in a cylinder when a vacuum pump removes of the air remaining in the cylinder at a time.

(iii) The cost of digging a well after every metre of digging, when it costs 150 for the first metre and rises by 50 for each msubsequent metre.

(iv) The amount of money in the account every year when 10000 is deposited at compound interest at 8% per annum.

Solution:
(i) Let T_n denotes the taxi fare in n^th km.
According to question,
T₁ = 15 km;
T₂ = 15 + 8 = 23;
T₃ = 23 + 8 = 31
Now, T₃ – T₂ = 31 – 23 = 8
T₂ – T₁ = 23 – 15 = 8
Here, T₃ – T₂ = T₂ – T₁ = 8
∴ given situation form an AP.

(ii) Let T_n denotes amount of air present in a cylinder.
According to question,
T₁ = x;
T₂ = x – \(\frac{1}{4}\)x
= \(\frac{4-1}{4}\)x = \(\frac{3}{4}\)x
T₃ = \(\frac{3}{4} x-\frac{1}{4}\left[\frac{3}{4} x\right]=\frac{3}{4} x-\frac{3}{16} x\)

= \(\left(\frac{12-3}{16}\right) x=\frac{9}{16}\)x and so on
Now, T₃ – T₂ = \(\frac{9}{16}\)x – \(\frac{3}{4}\)x
= \(\left(\frac{9-12}{16}\right) x=-\frac{3}{16}\)x

T₂ – T₁ = \(\frac{3}{4}\)x – x
= \(\left(\frac{3-4}{4}\right) x=-\frac{1}{4}\)x
Here, T₃ – T₂ ≠ T₂ – T₁
∴ given situation donot form an AP.

(iii) Let T_n denotes cost of digging a well for the nth metre,
According to question,
T₁ = ₹ 150; T₂ = (150 + 50) = ₹ 200;
T₃ = ₹ (200 + 5o) = 250 and so on
Now, T₃ – T₂ = ₹ (250 – 200) = 50
T₂ – T₁ = ₹ (200 – 150) = 50
Here, T₃ – T₂ = T₂– T₁ = 50
∴ given situation form an A.P.

(iv) Let T_n denotes amount of money in the nth year.
According to question
T₁ = ₹ 10,000
T₂ = ₹ 10,000 + ₹ \(\left[\frac{10,000 \times 8 \times 1}{100}\right]\)
= ₹ 10,000 + ₹ 800 = ₹ 10,800
T₃ = ₹ 10,800 + ₹ \(\left[\frac{10,800 \times 8 \times 1}{100}\right]\)
= ₹ 10,800 + ₹ 864
= ₹ 11,640 and so on.
Now, T₃ – T₂ = ₹ (11,640 – 10,800) = ₹ 840
T₂ – T₁ = ₹ (10,800 – 10,000) = ₹ 800
Here, T₃ – T₂ ≠ T₂ – T₁
∴ given situation do not form an A.P.

Question 2.
Write first four terms of the AP, when the first term a and the common difference d are given as follows:
(1) a = 10, d = 10
(ii) a = -2, d = 0
(iii) a = 4, d = -3
(iv) a = -1, d = \(\frac{1}{2}\)
(w) a = -1.25, d = -0.25
Solution:
(i) Given that first term = a = 10
and common difference = d = 10
∴ T₁ = a = 10;
T₂ = a + d = 10 + 10 = 20;
T₃ = a + 2d
= 10 + 2 × 10 = 10 + 20 = 30;
T₄ = a + 3d = 10 + 3 × 10
= 10 + 30 = 40
Hence, first four terms of an A.P. are 10, 20, 30, 40………….

(ii) Given that first term = a = -2
and common iifference = d = 0
∴ T₁ = a = -2;
T₂ = a + d = -2 + 0 = -2
T₃ = a + 2d = -2 + 2 × 0 = -2
T₄ = a + 3d = -2 + 3 × 0 = -2
Hence, first four terms of an A.P. are -2, -2, -2, -2,…………….

(iii) Given that first term = a = 4
and common difference = d = -3
∴ T₁ = a = 4;
T₂= a + d = 4 – 3 = 1
T₃ = a + 2d = 4 + 2(-3) = 4 – 6 = -2
T₄ = a + 3d = 4 + 3(-3) = 4 – 9 = -5
Hence, first four terms of an A.P. are 4, 1, -2, -5, ……….

(iv) Given that first term = a = -1
and common difference = d = \(\frac{1}{2}\)
∴ T₁ = a = -1; T₂ = a + d
= -1 + \(\frac{1}{2}\) = \(-\frac{1}{2}\)
T₃ = a + 2d = -1 + 2(\(\frac{1}{2}\))
= -1 + 1 = 0
T₄ = a + 3d = -1 + 3(\(\frac{1}{2}\))
= \(\frac{-2+3}{2}=\frac{1}{2}\)
Hence, first four terms of an AP are -1, –\(\frac{1}{2}\), 0, \(\frac{1}{2}\), …………..

(v) Given that first term = a = – 1.25
and common difference = d = – 0.25
∴ T₁ = a = – 1.25;
T₂ = a + d = – 1.25 – 0.25 = -1.50
T₃ = a + 2d = – 1.25 + 2(- 0.25)
= – 1.25 – 0.50 = – 1.75
T₄ = a + 3d = – 1.25 + 3(- 0.25)
= – 1.25 – 0.75 = – 2
Hence, first four terms of an A.P. are – 1.25, – 1.50, – 1.75, – 2, ……………..

Question 3.
For the following APs, wilte the first term and the common difference:
(i) 3, 1, -1, -3, …………
(ii) 5, -1, 3, 7, ………….
(iii) \(\frac{1}{3}, \frac{5}{3}, \frac{9}{3}, \frac{13}{3}\), …………..
(iv) 0.6, 1.7, 2.8, 3.9, ………..
Solution:
(i) Given A.P., is 3, 1, -1, -3, ………
Here T₁ = 3, T₂ = 1,
T₃ = -1, T₄ = -3
First term = T₁ = 3
Now, T₂ – T₁ = 1 – 3 = – 2
T₃ – T₂ = – 1 – 1 = -2
T₄ – T₃ = -3 + 1 = -2
∴ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = – 2
Hence, common difference = – 2 and first term = 3.

(ii) Given A.P. is – 5, – 1, 3, 7, ………….
Here T₁ = – 5, T₂ = – 1,
T₃ = 3, T₄ = 7
First term T₁ = -5
Now, T₂ – T₁ = -1 + 5 = 4
T₃– T₂ = 3 + 1 = 4
T₄ – T₃ = 7 – 3 = 4
∴ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = 4
Hence, common difference = 4 and first term = – 5.

(iii) Given AP. is:
\(\frac{1}{3}, \frac{5}{3}, \frac{9}{3}, \frac{13}{3}, \ldots\)
Here T₁ = \(\frac{1}{3}\), T₂ = \(\frac{5}{3}\),
T₃ = \(\frac{9}{3}\), T₄ = \(\frac{13}{3}\)
First term = T₁ = \(\frac{1}{3}\)
Now, T₂ – T₁ = \(\frac{5}{3}-\frac{1}{3}=\frac{5-1}{3}=\frac{4}{3}\)
T₃ – T₂ = \(\frac{9}{3}-\frac{5}{3}=\frac{9-5}{3}=\frac{4}{3}\)
T₄ – T₃ = \(\frac{13}{3}-\frac{9}{3}=\frac{13-9}{3}=\frac{4}{3}\)
∴ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = \(\frac{4}{3}\)

Hence, common difference = \(\frac{4}{3}\) and first term = \(\frac{1}{3}\).

(iv) Given A.P. is 0.6, 1.7, 2.8, 3.9,…
Here, T₁ = 0.6, T₂ = 1.7, T₃ = 2.8, T₄ = 3.9
First term = T₁ = 0.6
Now, T₂ – T₁ = 1.7 – 0.6 = 1.1
T₃ – T₂ = 2.8 – 1.7 = 1.1
T₄ – T₃ = 3.9 – 2.8 = 1.1
Hence, common difference = 1.1 and first term = 0.6.

Question 4.
WhIch of the following are APs? If they form an AP, find the common difference d and write three more terms.
(i) 2, 4, 8, 16
(ii) 2, \(\frac{5}{2}\), 3, \(\frac{7}{2}\), ………
(iii) – 1.2, – 3.2, – 5.2, – 7.2, ………….
(iv) – 10, – 6, – 2, 2, ………….
(v) 3, 3 + √2, 3 + 2√2, 3 + 3√2, ……….
(vi) 0.2, 0.22, 0.222, 0.2222, ………….
(vii) 0, -4, -8, -12, …………..
(viii) \(-\frac{1}{2}\), \(-\frac{1}{2}\), \(-\frac{1}{2}\), \(-\frac{1}{2}\), ………..
(ix) 1, 3, 9, 27 …………….
(x) a, 2a, 3a, 4a, ………………
(xi) a, a², a³, a⁴, ……………….
(xii) √2, √8, √18, √32, …………
(xiii) √3, √6, √9, √12, ……………..
(xiv) 1², 3², 5², 7², ………..
(xv) 1², 5², 7², 73, ………….

Solution:
(i) Given terms are 2, 4, 8, 16 ………………
Here T₁ = 2, T₂ = 4, T₃ = 8, T₄ = 16
T₂ – T₁ = 4 – 2 = 2
T₃ – T₂ = 8 – 4 = 4
∵ T₂ – T₁ ≠ T₃ – T₂
Hence, given terms do not form an A.P.

(ii) Given terms are 2, \(\frac{5}{2}\), 3, \(\frac{7}{2}\), ………
Here T₁ = 2, T₂ = 4, T₃ = 3, T₄ = 16
T₂ – T₁ = \(\frac{4}{4}\) – 2 = \(\frac{5-4}{2}\) = \(\frac{1}{2}\)
T₃ – T₂ = 3 – \(\frac{5}{2}\) = \(\frac{6-5}{2}=\frac{1}{2}\)
T₄ – T₃ = \(\frac{7}{2}-3=\frac{7-6}{2}=\frac{1}{2}\)
∵ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = \(\frac{1}{2}\)
∴ Common difference = d = \(\frac{1}{2}\)
Now, T₅ = a + 4d = 2 + 4\(\frac{1}{2}\) = 4

T₆ = a + 5d = 2 + 5(\(\frac{1}{2}\)) = \(\frac{4+5}{2}=\frac{9}{2}\)

T₇ = a + 6d = 2 + 6(\(\frac{1}{2}\)) = 2 + 3 = 5.

(iii) Given terms are – 1.2, – 3.2, – 5.2, – 7.2, …………
Here T₁ = – 1.2, T₂ = – 3.2,
T₃ = – 5.2, T₄ = – 7.2
T₂ – T₁ = – 3.2 + 1.2 = – 2
T₃ – T₂ = – 5.2 + 3.2 = – 2
T ₄ – T₃ = – 7.2 + 5.2 = – 2
∵ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = – 2
∴ Common difference = d = – 2
Now, T₅ = a + 4d = – 1.2 + 4(-2) = – 1.2 – 8 = – 9.2
T₆ = a + 5d = – 1.2 + 5(-2) = – 1.2 – 10 = – 11.2
T₇ = a + 6d = – 1.2 + 6(-2) = -1.2 – 12 = – 13.2

(iv) Given terms are – 10, – 6, – 2, 2, ………..
Here T₁ = – 10,T₂ = – 6
T₃ = – 2, T₄=2 .
T₂ – T₁ = – 6 + 10 = 4
T₃ – T₂ = – 2 + 6 =4
T₄ – T₃ = 2 + 2 = 4
∵ T₂ – T₁=T₃ – T₂ = T₄ – T₃ = 4 .
∴ Common difference = d = 4
Now, T₅ = a + 4d = – 10 + 4(4) = – 10 + 16 = 6
T₆ = a + 5d = – 10 + 5(4) = – 10 + 20 = 10
T₇ = a + 6d = – 10 + 6(4) = – 10 + 24 = 14.

(v) Given terms are 3, 3 + √2, 3 + 2√2, 3 + 3√2, …………
Here T₁ = 3, T₂ = 3 + √2,
T₃ = 3 + 2√2, T₄= 3 + 3√2
T₂ – T₁ = 3 + √2 – 3 = √2
T₃ – T2 = 3 + 2√2 – (3 + √2)
= 3 + 2√2 – 3 – √2 = √2
T₄ – T₃ = 3 + 3√2 – (3 + 2√2)
= 3 + 3√2 – 3 – 2√2 = √2
∵ T₂ -T₁ = T₃ – T₂ = T₄ – T₃ = √2
∴ Common difference = d = √2
Now, T₅ = a + 4d = 3 + 4(√2) = 3 + 4√2
T₆ = a + 5d = 3 + 5√2
T₇ = a + 6d = 3 + 6√2

(vi) Given terms are 0.2, 0.22, 0.222, 0.2222, …………..
Here Here T₁ = 0.2, T₂ = 0.22,
T₃ = 0.222, T₄ = 0.2222.
T₂ – T₁ = 0.22 – 0.2 = 0.02
T₃ – T₂ = 0.222 – 0.22 = 0.002
∵ T₂ – T₁ ≠ T₃ – T₂
∴ given terms do not form an A.P.

(vii) Given terms are 0, -4, -8, -12
Here T₁ = 0, T₂ = -4,
T₃ = -8, T₄ = -12
T₂ – T₁ = – 4 – 0 = -4
T₃ – T₂= – 8 + 4 = -4
T₄ – T₃= – 12 + 8 = -4.
T₂ – T₁ = T₃ – T₂ = T₄ – T₃
∴ Common difference = d = -4
Now, T₅= a + 4d = 0 + 4(-4) = -16
T₆ = a + 5d = 0 + 5(-4) = -20
T₇ = a + 6d = 0 + 6(-4) = -24.

(viii) Given terms are \(-\frac{1}{2}\), \(-\frac{1}{2}\), \(-\frac{1}{2}\), \(-\frac{1}{2}\), ……….
Here T₁ = \(-\frac{1}{2}\), T₂ = –\(\frac{1}{2}\)
T₃ = \(-\frac{1}{2}\), T₄ = \(-\frac{1}{2}\)
T₂ – T₁ = \(-\frac{1}{2}\) + \(\frac{1}{2}\) = 0
T₃ – T₂ = \(-\frac{1}{2}\) + \(\frac{1}{2}\) = 0
∵ T₂ – T₁ = T₃ – T₂ = 0
∴ Common difference = d = 0
Now, T₅ = T₆ = T₇ = –\(\frac{1}{2}\)
[∵ a = –\(\frac{1}{2}\), d = 0]

(ix) Given terms are 1, 3, 9, 27
T₁ = 1, T₂ = 3, T₃ = 9, T₄ = 27
T₂ – T₁ = 3 1 = 2
T₃ – T₂ = 9 – 3 = 6.
∵ T₂ – T₁ ≠ T₃ – T₂
∴ Given terms do not form an A.P.

(x) Given terms are a, 2a, 3a, 4a, …
T₁ = a, T₂ = 2a, T₃ = 3a, T4 = 4a
T₂ – T₁ = 2a – a = a
T₃ – T₂ = 3a – 2a = a
T₄ – T₃ = 4a – 3a = a
∵ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = a
∴ Common difference = d = a
Now T₅ = a + 4d = a + 4(a) = a + 4a = 5a
T₆ = a + 5d = a + 5a = 6a
T₇ = a + 6d = a + 6a = 7a

(xi) Given terms are a, a², a³, a⁴, …………
T₁ = a, T₂ = a², T3 = a³, T₄ = a⁴
T₂ – T₁ = a² – a
T₃ – T₂ = a³ – a²
∵ T₂ – T₁ ≠ T₃ – T₂
∴ Given terms do not form an A.P.

(xii) Given terms are √2, √8, √18, √32, …………
T₁ = √2, T₂ = √8, T₃ = √18, T₄ = √32
or T₁ = √2, T₂ = 2√2 T₃ = 3√2, T₄ = 4√2
T₂ – T₁ = 2√2 – √2 = √2
T₃ – T = 3√2 – 2√2 = √2
T₄ – T₃ = 4√2 – 3√2 = √2
∵ T₂ – T₁ = T₃ – T₂ = T₄ – T₃= √2
∴ Common difference = d = √2
Now, T₅ = a + 4d = √2 + 4√2 = 5√2
T₆ = a + 5d = √2 + 5√2 = 6√2
T₇ = a + 6d = √2 + 6√2 = 7√2

(xiii) Given terms are √3, √6, √9, √12, ……………..
T₁ = √3, T₂= √6, T₃= √9, T₄= √12
or T₁ = √3, T₂ = √6, T₃ = 3, T₄ = 2√3
T₄ – T₁ = √6 – √3
T₃ – T₂ = 3 – √6
∵ T₂ – T₁ ≠ T₃ – T₂
∴Given terms do not form an A.P.

(xiv) Given terms are 1², 3², 5², 7², ………..
T₁ = 1², T₂ = 3², T₃ = 5², T₄ = 7²
or T₁ = 1, T₂ = 9, T₃ = 25, T₄ = 49
T₄ – T₁ = 9 – 1 = 8
T₃ – T₂ = 25 – 9 = 16
∵ T₂ – T₁ ≠ T₃ – T₂
∴ Given terms do not form an A.P.

(xv) Given terms are 12, 52, 72, 73
T₁ = 12, T₂ = 52, T₃ = 72, T₄ = 73
or T₁ = 1, T₂ = 25, T₃ = 49, T₄ = 73
T₂ – T₁ = 25 – 1 = 24
T₃ – T₂ =49 – 24= 24
T₄ – T₃ = 73 – 49 = 24
∵ T₂ – T₁ = T₃ – T₂ = T₄ – T₃ = 24
∴ Common difference = d = 24
T₅ = a + 4d = 1 + 4(24) = 1 + 96 = 97
T₆ = a + 5d = 1 + 5(24) = 1 + 120 = 121
T₇ = a + 6d = 1 +6(24) = 1 + 144 = 145

Punjab State Board PSEB 10th Class Maths Book Solutions Chapter 4 Quadratic Equations Ex 4.4 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Maths Chapter 4 Quadratic Equations Ex 4.4

Question 1.
Find the nature of the roots of the following quadratic equations. If the real roots exist, find them:
(i)2x² – 3x + 5 = 0
(ii) 3x² – 4√3x + 4 = o
(iii) 2x² – 6x + 3 = 0
Solution:
(i) Given quadratic equation is, 2x² – 3x + 5 = 0
Compare it with ax² + bx + c = 0
a = 2, b = -3, c = 5
D = b² – 4ac
= (-3)² 4 × 2 × 5
= 9 – 40 = -31 < 0
Hence, given quadratic equation has no real roots.

(ii) Given quadratic equation is, 3x² – 4√3x + 4 = 0
Compare it with ax² + bx + c = 0
a = 3, b = -4√3, c = 4
D = b² – 4ac
= (-4√3)² – 4 × 3 × 4
= 48 – 48 = 0
given equation has real and equal roots.
Now, x = \(\frac{-b \pm \sqrt{\mathrm{D}}}{2 a}\)
= \(\frac{-(-4 \sqrt{3}) \pm \sqrt{0}}{2 \times 3}\) = \(\frac{2}{\sqrt{3}}\)
Hence, roots of given quadratic equation are \(\frac{2}{\sqrt{3}}\) and \(\frac{2}{\sqrt{3}}\).

(iii) Given quadratic equation is :
2x² – 6x + 3 = 0
Compare it with ax² + bx + c = 0
∴ a = 2, b = -6, c = 3
D = b² – 4ac
= (-6)² 4 × 2 × 3
= 36 – 24 = 12 > 0
∴ given equation has real and distinct roots.
Now, x = \(\frac{-b \pm \sqrt{\mathrm{D}}}{2 a}\)

= \(\frac{-(-6) \pm \sqrt{12}}{2 \times 2}\)

= \(\frac{6 \pm 2 \sqrt{3}}{4}\)

= \(\frac{3 \pm \sqrt{3}}{2}\)

= \(\frac{3+\sqrt{3}}{2}\) and \(\frac{3-\sqrt{3}}{2}\)
Hence, roots of given quadratic equation are \(\frac{3+\sqrt{3}}{2}\) and \(\frac{3+\sqrt{3}}{2}\).

Question 2.
Find the values of k for each of the following quadratic equations, so that they have two equal roots.
(i) 2x² + kx + 3 = 0
(ii) kx(x – 2) + 6 = 0
Solution:
(i) Given quadratic equation is : 2x² + kx + 3 = 0
Compare it with ax² + bx + c = 0
∴ a = 2, b = k, c = 3
∵ roots of the given quadratic equation are equal.
∴ D = 0
b² – 4ac = 0
Or(k)² – 4 × 2 × 3 = 0
Or k² – 24 = 0
Or k² = 24
Or k = ±√24
Or k = ±2√6.

(ii) Given quadratic equation is:
kx (x – 2) + 6 = 0
Or k – 2kx + 6 = 0
Compare it with ax² + bx + c = 0
∴ a = k, b = -2k, c = 6
∵ roots of the given quadratic equation are equal
∴ b² – 4ac = 0
Or(-2k)² – 4 × k × 6 = 0
Or 4k² – 24k = 0
Or 4k[k – 6]= 0
Either 4k = 0 Or k- 6 = 0
k = 0 Or k = 6
∴ k = 0, 6.

Question 3.
Is it possible to design a rectangular mango grove whose length is twice its breadth, and the area is 800 m2? If so, find
its length and breadth.
Solution:
Let breadth of rectangular grove = x m
and length of rectangular grove = 2x m
Area of rectangular grove = length × breadth
= [x × 2x] m² = 2 × 2 m²
According to question
2x² = 800
x² = \(\frac{800}{2}\) = 400
x = ± √400
x = ± 20.
∵ length of rectangle cannot be negative.
So, we reject x = -20
∴ x = 20
∴ breadth of rectangular grove = 20 m
and length of rectangular grove = (2 × 20) m = 40 m.

Question 4.
Is the following situation possible?If so, determine their present ages. The sum of the ages of two friends is 20 years. Four years ago, the product of their ages in years was 48.
Solution:
Let age of one friend = x years
and age of 2nd friend = (20 – x) years
Four years ago,
Age of 1st friend = (x – 4) years
Age of 2nd friend = (20 – x – 4) years = (16 – x) years
∴ Their product = (x – 4) (16 – x)
= 16x – x2 – 64 + 4x
= – x² + 20x – 64
According to Question
– x² + 20x – 64 = 48
Or – x² + 20x – 64 – 48 = 0
Or – x² + 20x – 112 = 0
Or x² – 20x + 112 = 0 …………….(1)
Compare it with ax² + bx + c = 0
∴ a = 1, b = -20, c = 112
D = b² – 4ac
= (-20)² – 4× 1 × 112
= 400 – 448 = -48 < 0
∴ roots are not real
then no real value of x satisfies the quadratic equation (1).
Hence, given situation is not possible.

Question 5.
Is it possible to design a rectangular park of perimeter 80 m and area 400 m2 ? If so, find its length and breadth.
Solution:
Let length of rectangular park = x m
Breadth of rectangular park = y m
∴ Perimeter of rectangular park = 2 (x + y) m
and area of rectangular park = xy m²
According to 1st condition
2 (x + y) = 80
x + y = \(\frac{80}{2}\) = 40
y = 40 – x …………(1)
According to 2nd condition,
xy = 400
x (40 – x) = 400 [using (1)]
Or 40x – x² = 400
Or 40x – x² – 400 = 0
Or x² – 40x + 400 = 0
Compare it with ax² +bx + c = 0
a = 1, b = -40, c = 400
D = b² – 4ac
= (-40)² – 4 × 1 × 400
= 1600 – 1600 = 0
Now, x = \(\frac{-b \pm \sqrt{\mathrm{D}}}{2 a}\)

= \(\frac{-(-40) \pm \sqrt{0}}{2 \times 1}\)

= \(\frac{40}{2}\) = 20
When x = 20 then from (1)
y = 40 – 20 = 20
∴ Length and breadth of rectangular park are equal of measure 20 m.
Hence, given rectangular park exist and it is a square.

Punjab State Board PSEB 10th Class Maths Book Solutions Chapter 4 Quadratic Equations Ex 4.3 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Maths Chapter 4 Quadratic Equations Ex 4.3

Question 1.
Find the roots of the following quadratic equations if they exist, by the method of completing the square:
(i) 2x² + 7x + 3
(ii) 2x² + x – 4 = 0
(ili) 4x² + 4√3x + 3 = 0
(iv) 2x² + x + 4 = 0
Solution:
(i) Given quadratic equation is
2x² – 7x + 3 = 0
Or 2x² – 7x = -3
Or x² – \(\frac{7}{2}\)x = –\(\frac{3}{2}\)
Or x² – \(\frac{7}{2}\)x + (\(\frac{-7}{4}\))² = \(\frac{-3}{2}+\left(\frac{-7}{4}\right)^{2}\)

Or \(\left(x-\frac{7}{4}\right)^{2}=\frac{-3}{2}+\frac{49}{16}\)

Or \(\left(x-\frac{7}{4}\right)^{2}=\frac{-24+49}{16}\)

Or \(\left(x-\frac{7}{4}\right)^{2}=\frac{25}{16}\)

Or x – \(\frac{7}{4}\) = \(\pm \sqrt{\frac{25}{16}}=\pm \frac{5}{4}\)

Case I:
When x – \(\frac{7}{4}\) = \(\frac{5}{4}\)
Or x = \(\frac{5}{4}+\frac{7}{4}=\frac{5+7}{4}\)
Or x = \(\frac{12}{4}\) = 3

Case II:
When x – \(\frac{7}{4}\) = \(\frac{-5}{4}\)
Or x = \(\frac{-5}{4}+\frac{7}{4}=\frac{-5+7}{4}\)
Or x = \(\frac{2}{4}=\frac{1}{2}\)
Hence, roots of given quadratic equation is 3, \(\frac{1}{2}\).

(ii) Given Quadratic Equation is
2x² + x – 4 = 0
Or 2x² + x = 4
Or x² + \(\frac{1}{2}\)x = \(\frac{4}{2}\)

Case I:
When x + \(\frac{1}{4}\) = \(\frac{-\sqrt{33}}{4}\)
Or x = \(-\frac{\sqrt{33}}{4}-\frac{1}{4}\)
Or x = \(\frac{-\sqrt{33}-1}{4}\)
Hence, roots of given quadratic equation are \(\frac{-1+\sqrt{33}}{4}\) and \(\frac{-1-\sqrt{33}}{4}\).

(iii) Given quadratic equation is
4x² + 4√3x + 3 = 0
Or 4x² + 4√3x = -3
Or x² + \(\frac{4 \sqrt{3}}{4}\)x = \(\frac{-3}{4}\)
Or x² + √3x = \(\frac{-3}{4}\)
Or x² + √3x + \(\left(\frac{\sqrt{3}}{2}\right)^{2}=\frac{-3}{4}+\left(\frac{\sqrt{3}}{2}\right)^{2}\)
Or \(\left(x+\frac{\sqrt{3}}{2}\right)^{2}=\frac{-3}{4}+\frac{3}{4}\)
or (x + \(\frac{\sqrt{3}}{2}\))² = 0
(x + \(\frac{\sqrt{3}}{2}\)) (x + \(\frac{\sqrt{3}}{2}\)) = 0
Either x + \(\frac{\sqrt{3}}{2}\) = 0
x = –\(\frac{\sqrt{3}}{2}\)
Or x + \(\frac{\sqrt{3}}{2}\) = 0
Or x = –\(\frac{\sqrt{3}}{2}\)
Hence, roots of given quadratic equation are –\(\frac{\sqrt{3}}{2}\) and –\(\frac{\sqrt{3}}{2}\).

(iv) Given quadratic equation is
2x² + x + 4 = 0
2x² + x = -4
x² + \(\frac{1}{2}\)x = \(-\frac{4}{2}\)
Or x² + \(\frac{1}{2}\)x + (\(\frac{1}{4}\))² = -2 + (\(\frac{1}{4}\))²

Or \(\left(x+\frac{1}{4}\right)^{2}=-2+\frac{1}{16}\)
Or \(\left(x+\frac{1}{4}\right)^{2}=\frac{-32+1}{16}\)
Or \(\left(x+\frac{1}{4}\right)^{2}=\frac{-31}{16}<0\)

∴ square of any number cannot be negative. So, (x + \(\frac{1}{4}\))² cannot be negative for any real x.
∴ There is no real x whith satisfied the given quadratic equation.
Hence, given quadratic equation has no real roots.

Question 2.
Find the roots of the quadratic equations given in Q. 1 by applying the quadratic formula. Which of the above two
methods do you prefer, and why?
Solution:
(i) Given quadratic equation is
2x² – 7x + 3 = 0
Compare it with ax² + bx + c = 0
a = 2, b = -7, c = 3
Now, b² – 4ac = (-7)² 4 x 2 x 3
= 49 – 24
= 25 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-7) \pm \sqrt{25}}{2 \times 2}=\frac{7 \pm 5}{4}\)
= \(\frac{7+5}{4} \text { and } \frac{7-5}{4}\)
= \(\frac{12}{4} \text { and } \frac{2}{4}\)
= 3 and \(\frac{1}{2}\)
Hence, 3 and \(\frac{1}{2}\) are the roots of given quadratic equation.

(ii) Given quadratic equation is
2x² + x – 4 = 0
Compare it with ax² + bx + c = 0
∴ a = 2, b = 1, c = -4
Now,
b² – 4ac = (1)² – 4 × 2 × 4
= 1 + 32 = 33 > 0
x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-1 \pm \sqrt{33}}{2 \times 2}=\frac{-1 \pm \sqrt{33}}{4}\)
= \(\frac{-1+\sqrt{33}}{4}\) and \(\frac{-1-\sqrt{33}}{4}\)
Hence, \(\frac{-1+\sqrt{33}}{4}\) and \(\frac{-1-\sqrt{33}}{4}\) are the roots of given quadratic equation.

(iii) Given quadratic equation is
4x² + 4√3x + 3 = 0
Compare it with ax² + bx + c = 0
a = 4, b = 4√3, c = 3
b² – 4ac = (4√3)² – 4 × 4 × (3)
= 48 – 48 = 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)

= \(\frac{-4 \sqrt{3} \pm \sqrt{0}}{2 \times 4}\)

= \(-\frac{4 \sqrt{3}}{8}\), \(-\frac{4 \sqrt{3}}{8}\)

= –\(\frac{\sqrt{3}}{2}\), –\(\frac{\sqrt{3}}{2}\)

Hence, –\(\frac{\sqrt{3}}{2}\), –\(\frac{\sqrt{3}}{2}\) are the roots of given quadratic equation.

(iv) Given quadratic equation is 2x² + x + 4 = 0
Compare it with ax² + bx + c = 0
∴ a = 2, b = 1, c = 4
Now, b² – 4ac = (1)² – 4 × 2 × 4
= 1 – 32 = -31 < 0
But
x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
Since the square of a real number cannot be negative, therefore x will not have any real value.
Hence, there are no real roots for the given quadratic equation.

From above two questions, we used two methods to find the roots of the quadratic equations. It is very clear from above discussion that quadratic formula method is very convenient as compared to method of completing the square.

Question 3.
Find the roots of the following equations:

(i) x – \(\frac{1}{x}\) = 3, x ≠ 0
(ii) \(\frac{1}{x+4}-\frac{1}{x-7}=\frac{11}{30}\), x ≠ -4, 7
Solution:
(i) Given Equation is
x – \(\frac{1}{x}\) = 3
Or \(\frac{x^{2}-1}{x}\) = 3
Or x² – 1 = 3x
Or x² – 3x – 1 = 0
Compare it with ax² + bx + c = 0
∴ a = 1, b = -3, c = -1
Now, b² – 4ac = (-3)² – 4 . 1 . (-1)
= 9 + 4 = 13 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-3) \pm \sqrt{13}}{2 \times 1}\)
= \(\frac{3 \pm \sqrt{13}}{2 \times 1}\)
= \(\frac{3+\sqrt{13}}{2}\) and \(\frac{3-\sqrt{13}}{2}\)
Hence, \(\frac{3+\sqrt{13}}{2}\) and \(\frac{3-\sqrt{13}}{2}\) are the roots of given quadratic equation.

(ii) Given equation is

-11 × 30 = 11 (x2 – 3x – 28)
Or -30 = x² – 3x – 28
Or x² – 3x – 28 + 30 = 0
Or x² – 3x + 2 = 0
Compare it with ax² + bx + c = 0
a = 1, b = – 3, c = 2
Now, b² – 4ac = (-3)² – 4 × 1 ×2
= 9 – 8 = 1 > 0
x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-3) \pm \sqrt{1}}{2 \times 1}=\frac{3 \pm 1}{2}\)
= \(\frac{3+1}{2}\) and \(\frac{3+1}{2}\)
= \(\frac{4}{2}\) and\(\frac{2}{2}\) and 1
Hence, 2 and 1 are the roots of given quadratic equation.

Question 4.
The sum of the reciprocals of Rehman’s age (in years) 3 years ago and 5 years from now is \(\frac{1}{3}\). F1nd his present age.
Solution:
Let Rehman’s present age = x years
3 years ago Rehman’s age (x – 3) years
5 years from now Rehman’s age =(x + 5) years
According to question,
\(\frac{1}{x-3}+\frac{1}{x+5}=\frac{1}{3}\)

Or \(\frac{x+5+x-3}{(x-3)(x+5)}=\frac{1}{3}\)

Or \(\frac{2 x+2}{x^{2}+5 x-3 x-15}=\frac{1}{3}\)

Or \(\frac{2 x+2}{x^{2}+2 x-15}=\frac{1}{3}\)
Or 6x + 6 = x² + 2 -15
Or x² + 2x – 15 – 6x – 6 = 0
Or x² – 4x – 21 = 0, which is quadratic in x.
So compare it with ax² + bx + c =0
a = 1, b = -4, c = -21
Now, b² – 4ac = (- 4)² 4 × 1 × (-21)
= 16 + 84 = 100 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
x = \(\frac{-(-4) \pm \sqrt{100}}{2 \times 1}\)
= \(\frac{4 \pm 10}{2}\)
= \(\frac{4+10}{2}\) and \(\frac{4-10}{2}\)
\(\frac{14}{2}\) and \(\frac{-6}{2}\)
= 7 and -3
∵ age cannot be negative,
so, we reject x = – 3
∴ x = 7
Hence, Rehman’s present age = 7 years.

Question 5.
In a class test, the sum of Shefall’s marks in Mathematics and English is 30. Had she got 2 marks more in Mathematics and 3 marks less ¡n English, the product of their marks would have been 210. Find her marks In the two subjects.
Solution:
Let Shefali get marks in Mathematics = x
Shefali’s marks in English = 30 – x
According to 1st condition,
Shefali’s marks in Mathematics = x + 2
and Shefali’s marks in English = 30 – x – 3 = 27 – x
∴ Their product = (x + 2) (27 – x)
= 27x – x² + 54 – 2x
= x² + 25x + 54
According to 2nd condition,
-x²+ 25x+ 54 = 210
Or -x² + 25x + 54 – 210 = 0
Or -x² + 25x – 156 = 0
Or x² – 25x+ 156 = o
Compare it with ax² + bx + c = O
a = 1, b = -25, c = 156
Now, b² – 4ac = (-25)² – 4 × 1 × 156
= 625 – 624 = 1 > 0
x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-25) \pm \sqrt{1}}{2 \times 1}\)
= \(\frac{25 \pm 1}{2}\)
= \(\frac{25+1}{2}\) and \(\frac{25-1}{2}\)
= \(\frac{26}{2}\) and \(\frac{24}{2}\)
= 13 and 12.

Case I:
When x = 13
then Shefaiis marks in Maths = 13
Shefali’s marks in English = 30 – 13 = 17.

Case II:
When x = 12
then Shefalis marks in Maths = 12
Shefali’s marks in English = 30 – 12 =18.
Hence, Shefalis marks in two subjects are 13 and 17 Or 12 and 18.

Question 6.
The diagonal of a rectangular field is 60 metres more than the shorter side. if the longer side is 30 metres more than the shorter side, find the sides of the field.
Solution:
Let shorter side of rectangular field = AD = x m

Longer side of rectangular field = AB = (x + 30) m
and diagonal of rectangular field = DB = (x + 60) m
In rectangle. the angle between the length and breadth is right angle.
∴ ∠DAB = 90°
Now, in right angled triangle DAB, using Pythagoras Theorem,
(DB)² = (AD)² + (AB)²
(x + 60)² = (x)² + (x + 30)²
Or x² + 3600 + 120x = x² + x² + 900 + 60x
Or x² + 3600 + 120x – 2x² – 900 – 60x = 0
Or -x² + 60x + 2700 = 0
Or x² – 60x – 2700 = 0
Compare it with ax² + bx + e = O
∴ a = 1, b = -60, c = -2700
and b² – 4ac = (-60)² – 4. 1 . (-2700)
= 3600 + 10800 = 14400 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-60) \pm \sqrt{14400}}{2 \times 1}\)

= \(\frac{60 \pm 120}{2}\)

= \(\frac{60+120}{2}\) and \(\frac{60-120}{2}\)
= \(\frac{180}{2}\) and \(\frac{-60}{2}\)
= 90 and – 30
∴ length of any side cannot be negative
So, we reject x = -30
∴ x = 90
Hence, shorter side of rectangular field = 90 m
Longer side of rectangular field = (90 + 30) m = 120 m.

Question 7.
The difference of squares of two numbers is 180. The square of the smaller number is 8 times the larger number. Find
the two numbers.
Solution:
Let larger number = x .
Smaller number = y
According to 1st condition,
x² – y² = 180 ……………(1)
According to 2nd condition,
y² = 8x
From (1) and (2), we get
x² – 8x = 180
Or x² – 8x – 180 = 0
Compare it with ax² + bx + c = 0
∴ a = -1, b = -8, c = -180
and b² – 4ac = (-8)² – 4 × 1 × (-180)
= 64 + 720 = 784 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-(-8) \pm \sqrt{784}}{2 \times 1}\)
= \(\frac{8 \pm 28}{2}\)
= \(\frac{8+28}{2}\) and \(\frac{8-28}{2}\)
= \(\frac{36}{2}\) and \(\frac{-20}{2}\)
= 18 and -10
When x = – 10 then from (2),
y² = 8 (- 10) = – 80, which is impossible.
So, we reject x = – 10
When x = 18 then from (2).
y² = 8(18) = 144
Or y = ±√144
Or y = ± 12
Hence, required numbers are 18 and 12 Or 18 and -12.

Question 8.
A train travels 360 km ¡t a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.
Solution:
Let constant speed of the train = x km/hour
Distance covered by the train = 360 km
Time taken by the train = \(=\frac{\text { distance }}{\text { speed }}\)
(∵ speed = \(\frac{\text { Distance }}{\text { Time }}\))
= \(\frac{360}{x}\)
Increased speed of the train = (x + 5) km/hour
∴ Time taken by the train with increased speed = \(\frac{360}{x+5}\) hour
According to question

Or 1800 = x² + 5x
Or x² + 5x – 1800 = 0
Compare it with, ax² + bx + c = 0
a = 1, b = 5, c = – 1800
and b² – 4ac = (5)² 4 × 1 × (- 1800)
= 25 + 7200 = 7225 > 0

x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-5 \pm \sqrt{7225}}{2 \times 1}\)
= \(\frac{-5 \pm 85}{2}\)
= \(\frac{-5+85}{2}\) and \(\frac{-5-85}{2}\)
= \(\frac{80}{2}\) and \(\frac{-90}{2}\)
= 40 and – 45
∵ speed of any train cannot be negative.
So, we reject x = – 45
x = 40
Hence, speed of train = 40 km/hour.

Question 9.
Two water taps together can fill a tank in 9\(\frac{3}{8}\) hours. The tap of larger diameter takes 10 hours less than the smaller one to fill the tank separately. Find the time in which each tap can separately fill the tank.
Solution:
Let time taken by larger tap to fill the tank = x hours.
Time taken by smaller tap to fill the tank = (x + 10) hours
In case of one hour:
Larger tap can fill the tank = \(\frac{1}{x}\)
Smaller tap can fill the tank = \(\frac{1}{x+10}\)
∴ Larger and smaller tap fill the tank = \(\frac{1}{x}\) + \(\frac{1}{x+10}\) ………….(1)
But, two taps together can fill the tank = 9\(\frac{3}{8}\)hour = \(\frac{75}{8}\) hour
Now, two taps together can fill the tank in one hour = \(\frac{8}{75}\) ……………..(2)
From (1) and (2), we get
\(\frac{1}{x}+\frac{1}{x+10}=\frac{8}{75} \)

Or \(\frac{x+10+x}{x(x+10)}=\frac{8}{75}\)

Or \(\frac{2 x+10}{x^{2}+10 x}=\frac{8}{75}\)

Or 75(2x + 10) = 8(x² + 10x)
Or 150x + 750 = 8x² + 80x
Or 8x² + 80x – 150x – 750 = 0
Or 8x² – 70x – 750 = 0
Or 4x² – 35x – 375 = 0
Compare it with ax² + bx + c = 0
∴ a = 4, b = -35, c = -375
and b² – 4ac = (35)² -4 × 4 × (-375)
= 1225 + 6000 = 7225 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)

= \(\frac{-(-35) \pm \sqrt{7225}}{2 \times 4}\)

= \(\frac{35 \pm 85}{8}\)

= \(\frac{35+85}{8}\) and \(\frac{35-85}{8}\)

= \(\frac{120}{8}\) and \(\frac{-50}{8}\)

= 15 and \(\frac{-25}{4}\)

∵ time cannot be negative.
So,we reject x = \(\frac{-25}{4}\)
∴ x = 15
Hence, larger water tap fills the tank = 15 hours
and smaller water tap fills the tank = (15 + 10) hours = 25 hours.

Question 10.
An express train takes 1 hour less than a passenger train to travel 132 km between Mysore and Bangalore (without taking into consideration the time they stop to intermediate stations), if the average speed of the express train is 11 km/hr more than that of the passenger train, find the average speed of the two trains.
Solution:
Let average speed of passenger train = x km/hour
Average speed of express train = (x+ 11) km/hour
Distance between Mysore and Bangalore = 132 km
Time taken by passenger train = \(\frac{132}{x}\) hour
[∵ Speed = \(=\frac{\text { Distance }}{\text { Time }}\) ]
Time taken by express train‚ = \(\frac{132}{x+11}\) hour
According to question,

Or 1452 = x² + 11x
Or x² + 11x – 1452 = 0
Compare it with ax² + bx + c = 0
∴ a = 1, b = 11, c = -1452
and b² – 4ac = (11)² – 4 × 1 × (- 1452)
= 121 + 5808 = 5929 > 0
∴ x = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)
= \(\frac{-11 \pm \sqrt{5929}}{2 \times 1}\)

= \(\frac{-11 \pm 77}{2}\)

= \(\frac{-11+77}{2}\) and \(\frac{-11-77}{2}\)

= \(\frac{66}{2}\) and \(\frac{-88}{2}\) = 33 and -44

∵ speed of any train cannot be negative
∴ x = 33
Hence, speed of passenger train = 33 km/hour
and speed of express train = (33 + 11) km/hour = 44 km/hour.

Question 11.
Sum of the areas of two squares is 468 m². If the difference of their perimeters
is 24 m, find the sides of the two squares.
Solution:
In case of larger square
Let length of each side of square = x m
Area of square = x² m²
Perimeter of square = 4x m

In case of smaller square:

Let lenth of each side of square = y m
Area of square = y² m²
Perimeter of square = 4y m
According to 1st condition,
x² + y² = 468 …………….(1)
According to 2nd condition,
4x – 4y = 24
Or 4(x – y) = 24
Or x – y = 6
x = 6 + y
From (1) and (2), we get
(6 + y)² + y² = 468
Or 36 + y² + 12y + y² = 468
Or 2y² + 12y + 36 – 468 = 0
Or 2y² + 12y – 432 = 0
Or y² + 6y – 216 = 0
Compare it with ay² + by + c = 0
∴ a = 1, b = 6, c = -216
and b² – 4ac = (6)² – 4 × 1 × (- 216) = 36 + 864 = 900 > 0
∴ y = \(\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}\)

= \(\frac{-6 \pm \sqrt{900}}{2 \times 1}\)

= \(\frac{-6 \pm 30}{2}\)

= \(\frac{-6+30}{2}\) and \(\frac{-6-30}{2}\)

= \(\frac{24}{2}\) and \(\frac{-36}{2}\) = 12 and -18

∵ length of square cannot be negative
So, we reject y = – 18
∴ y = 12
From (2), x = 6 + 12 = 18
Hence, sides of two squares are 12 m and 18 m.

Punjab State Board PSEB 10th Class Maths Book Solutions Chapter 4 Quadratic Equations Ex 4.2 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Maths Chapter 4 Quadratic Equations Ex 4.2

Question 1.
Find the roots of the following quadratic equations by factorisation:
(i) x² – 3x – 10 = 0
(ii) 2x² + x – 6 = 0
(iii) √2x² + 7x + 5√2 = 0
(iv) 2 x² – x + \(\frac{1}{8}\) = 0
(v) 100x² – 20x + 1 = 0
Solution:
(i) Given quadratic
x² – 3x – 10 = 0
Or x² – 5x + 2x – 10 = 0
S = -3, p = -10
Or x (x – 5) + 2 (x – 5) = 0
Or (x – 5) (x + 2) = 0
Either x – 5 = 0 Or x + 2 = 0
x = 5 Or x = -2
Hence, 5 and -2 are roots of given Quadratic Equation.

(ii) Given quadratic equation
2x² + x – 6 = 0 =1
0r 2x² + 4x – 3x – 6 = 0
S = 1 P = -6 × 2 = -12
Or 2x (x + 2) -3 (x + 2) = 0
Or (x + 2) (2x – 3) = 0
Either x + 2 = 0 Or 2x – 3 = 0
x = -2 Or x = –\(\frac{3}{2}\)
Hence, – 2 and \(\frac{3}{2}\) are roots of given quadratic equation.

(iii) Given Quadratic Equation,
√2x² + 7x + 5√2 = 0
Or √2x² + 2x + 5x + 5√2 = 0
S = 7, P = √2 × 5√2 = 10
Or √2x (x + √2) + 5 (x + √2) = 0
Or (x + √2) (√2x + 5) = 0
Either x + √2 = 0 Or √2x + 5 = 0
x = -√2 Or x = –\(\frac{-5}{\sqrt{2}}\)
Hence, -√2 and \(\frac{-5}{\sqrt{2}}\) are roots of given quadratic equation.

(iv) Given quadratic equation
2x² – x + \(\frac{1}{8}\) = 0
Or \(\frac{16 x^{2}-8 x+1}{8}\) = 0
Or 16x² – 8x + 1 = 0
S = -8, P = 16 × 1 = 16
Or 16x² – 8x + 1 = 0
Or 16x² – 4x – 4x + 1 = 0
Or 4x(4x – 1) -1(4x – 1) = 0
Or (4x – 1) (4x – 1) = 0
Either 4x – 1 = 0
Or 4x – 1 = 0
x = \(\frac{1}{4}\) Or x = \(\frac{1}{4}\)
Hence, \(\frac{1}{4}\) and \(\frac{1}{4}\) are roots of given quadratic equation.

(v) Given quadratic equation,
100x² – 20x + 1 = 0
Or 100x² – 10x – 10x + 1 = 0
S = -20, P = 100 × 1 = 100
Or 10x(10x – 1) – 1 (10x – 1) = 0
Or (10x – 1)(10x – 1) = 0
Either 10x – 1 = 0 Or 10x – 1 = 0
x = \(\frac{1}{10}\) Or x = \(\frac{1}{10}\)
Hence, \(\frac{1}{10}\) and \(\frac{1}{10}\) are roots of given quadratic equation.

Question 2.
Solve the problems given in Example I. Statements of these problems are given below:
(i) John and Jivanti together have 45 marbles. Both of them lost S marbles each, and the product of the number of marbles they now have is 124. We would lfke to find out how many marbles they had to start with.

(ii) A cottage Industry produces a certain number of toys in a day. The cost of production of each toy (In rupees) was found to be 55 minus the number of toys produced in a day. On a particular day, the total cost of production was 750. We would like to find out the number of toys produced on that day.

Solution:
(i) Let the number of marbles John had be x.
Then the number of marbles Jivanti had = 45 – x
The number of marbles Íeft withJohn, when he lost 5 marbles = x – 5
The number of marbles left with Jivanti, when she lost 5 marbles = 45 – x – 5 = 40 – x
Therefore, their product = (x – 5) (40 – x)
= 40x – x² – 200 + 5x
= -x² + 45x – 200
According to question,
-x² + 45x – 200 = 124
Or -x² + 45x – 324 = 0
Or x² – 45x + 324 =0
Or x² – 36x – 9x + 324 = 0
S = -45, P = 324
Or x(x – 36) – 9(x – 36) = 0
Or (x – 36)(x – 9) = 0
Either x – 36 = 0, Or x – 9 = 0
x = 36 Or x = 9
∴ x = 36, 9
Hence, number of marbles they had to start with were 36 and 9 or 9 and 36.

(ii) Let the number of toys produced on that day be x.
Therefore, the cost of production (in rupees) of each toy that day = 55 – x
So, the total cost of production (in rupees) that day = x (55 – x)
According to question.
x(55 – x) = 750
Or 55x – x² = 750
Or -x² + 55x – 750 = 0
Or x² – 55x – 750 = 0
Or x² – 30x – 25x + 750=0
S = -33, P = 750
Or x(x – 30) – 25(x – 30) = 0
Or (x – 30)(x – 25) = 0
Either x – 30 = 0 Or x – 25 = 0
x = 30 Or x = 25
∴ x = 30, 25
Hence, number of toys produced on that day were 30 and 25 or 25 and 30.

Question 3.
Find two numbers whose sum is 27 and product is 182.
Solution:
Let one number = x
2nd number = 27 – x
Their product = x (27 – x) = 27x – x²
According to question,
27x – x² = 182
Or – x² + 27x – 182 = 0
Or x² – 27x + 182 = 0
S = -27, P = 182
Or x² – 13x – 14x + 182 = 0
Or x(x – 13) – 14(x – 13) = 0
Or (x – 13) (x – 14) = 0
Either x – 13 = 0 Or x – 14 = 0
x = 13 Or x = 14
x = 13, 14
Hence, two numbers are 13 and 14 Or 14 and 13.

Question 4.
Find two consecutive positive integers, sum of whose squares is 365.
Solution:
Let one positive integer = x
2nd positive integer = x + 1
According to question,
(x)² + (x + 1)² = 365
Or x² + x² + 1 + 2x = 365
Or 2x² + 2x + 365 = 0
Or 2x² + 2x – 364 = 0
Or x² + x – 182 = 0
Or x² + 14x – 13x – 182 = 0
S = 1, P = -182
Or x(x + 14) – 13(x + 14) = 0
(x + 14)(x— 13) = O
Either x + 14 = 0
Or x = -14
Or
x – 13 = 0
x = 13
∵ We have positive integers.
So, we reject x = – 14.
∴ x = 13
∴ One positive integer = 13
and 2nd positive integer = 13 + 1 = 14
Hence, required consecutive positive integers are 13 and 14.

Question 5.
The altitude of a right triangle is 7 cm less than its base. 1f the hypotenuse is 13 cm, find the other two sides.
Solution:
Let base of right triangle = x cm
Altitude of right triangle = (x – 7) cm
and hypotenuse of right triangle = 13 cm (Given)
According to Pythagoras Theorem,
(Base)² + (Altitude)² = (Hypotenuse)²
(x)² ÷ (x – 7)² = (13)²
Or x² + x² + 49 – 14x = 169
Or 2x² – 14x + 49 – 169 = 0
Or 2x² – 14x – 120 = 0
Or 2[x² – 7x – 60] = 0
Or x² – 7x – 60 = 0
Or x² – 12x + 5x – 60 = 0
S = – 7 P = – 60
Or x(x – 12) + 5(x – 12) = 0
Or (x – 12) (x + 5) = 0
Either x – 12 = 0 Or x + 5 = 0
x = 12 Or x= – 5
∵ Length of any triangle cannot be negative.
So, we reject x = – 5
∴ x = 12
Hence, base of right triangle = 12 cm
Altitude of right triangle = (12 – 7) cm = 5 cm.

Question 6.
A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was 90, find the number of articles produced and the cost of each article.
Solution:
Let, number of pottery articles produced by industry in one day = x
Cost of production of each article = ₹ (2x + 3)
∴ Total cost of production in panicular day = ₹ [x(2x + 3)] = ₹ (2x² + 3x)
According to question,
2x² + 3x = 90
2x² + 3x – 90 = 0
S = 3, P = 2 × -90 = -180
Or 2x² – 12x + 15x – 90 = 0
Or 2x (x – 6) + 15 (x – 6) = 0
Or (x – 6) (2x + 15) = 0
Either x – 6 = 0 Or 2x + 15 = 0
x = 6 Or x = \(\frac{-15}{2}\)
∵ number of articles cannot be negative
So, we reject x = 2
∴ x = 6
Hence, number of articles produced on certain day = 6
and cost of production of each article = ₹ [2 × 6 + 3] = ₹ 15.

Punjab State Board PSEB 10th Class Maths Book Solutions Chapter 4 Quadratic Equations Ex 4.1 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 10 Maths Chapter 4 Quadratic Equations Ex 4.1

Question 1.
Check whether the following are quadratic equations:
(i) (x + 1)² = 2(x – 3)
(ii) x² – 2x = (-2) (3 – x)
(iii) (x – 2) (x + 1) = (x – 1) (x + 3)
(iv) (x – 3)(2x + 1) = x (x + 5)
(v) (2x – 1) (x – 3) = (x + 5) (x – 1)
(vi) x² + 3x + 1 = (x – 2)
(vii) (x + 2)³ = 2x(x² – 1)
(viii) x³ – 4x² – x + 1 = (x – 2)³

Solution:
(i) Given that
(x + 1)² = 2(x – 3)
Or x² + 1 + 2x = 2x – 6
Or x² + 1 + 2x – 2x + 6 = 0
Or x² + 7 = 0
Or x² + 0x + 7 = 0
which is in the formof ax² + bx + c = 0;
∴ It is a quadratic equation.

(ii) Given that
x² – 2x = (-2) (3 – x)
Or x² – 2x = -6 + 2x
Or x² – 2x + 6 – 2x = 0
Or x² – 4x + 6 = 0
which is the form of ax² + bx + c = 0; a ≠ 0
∴ It is the quadratic equation.

(iii) Given that ,
(x – 2) (x + 1) = (x – 1) (x + 3)
Or x² + x – 2x – 2 = x² + 3x – x – 3
Or x² – x – 2 = x² + 2x – 3
Or x² – x – 2 – x² -2x + 3 = 0
Or -3x + 1 = 0 which have no term of x².
So it is not a quadratic equation.

(iv) Given that
(x – 3)(2x + 1) = x(x + 5)
Or 2x² + x – 6x – 3 = x² + 5x
Or 2x² – 5x – 3 – x² – 5x = 0
Or x² – 10x – 3 = 0
which is a form of ax² + bx + c = 0; a ≠ 0
∴ It is a quadratic equation.

(v) Given that ,
(2x – 1) (x – 3) = (x + 5) (x – 1)
0r2x² – 6x – x + 3 = x² – x + 5x – 5
Or 2x² – 7x + 3 = x² + 4x – 5
Or 2x² – 7x + 3 – x² – 4x + 5 = 0
Or x² – 11x + 8 = 0
which is a form of ax² + bx + c = 0; a ≠ 0
∴ It is a quadratic equation.

(vi) Given that
x²+3x+1 = (x – 2)²
Or x² + 3x + 1 = x² + 4 – 4x
Or x² + 3x + 1 – x² – 4 + 4x = 0
Or 7x – 3 = 0
which have no term of x².
So it is not a quadratic equation.

(vii) Given that
(x + 2)³ = 2x(x² – 1)
Or x³ + (2)³ + 3 (x)² 2 + 3(x)(2)² = 2x³ – 2x
Or x³ + 8 + 6x² + 12x = 2x³ – 2x
Or x³ + 8 + 6x² + 12x – 2x³ + 2x = 0
Or -x³ + 6x² + 14x + 8 = 0
Here the highest degree of x is 3. which is a cubic equation.
∴ It is not a quadratic equation.

(viii) Given that
x³ – 4x² – x+ 1= (x – 2)³
Or x³ – 4x² – x + 1 = x³ – (2)³ + 3(x)² (-2) + 3 (x) (-2)²
Or x³ – 4x² – x + 1 = x³ – 8 – 6x² + 12x
Or x³ – 4x² – x + 1 – x³ + 8 + 6x² – 12x = 0
Or 2x² – 13x + 9 = 0
which is in the form of ax² + bx +c = 0; a ≠ 0
∴ It is a quadratic equation.

Question 2.
Represent the following situations in the form of quadratic equations:
(i) The area of a rectangular plot is 528 m². The length of the plot (in metres) is one more than twice its breadth. We need to find the length and breadth of the plot.

(ii) The product of two consecutive positive integers is 306. We need to find the integers.

(iii) Rohan’s mother is 26 years older than him. The product of their ages (in years) 3 years from now will be 360. We would like to find Rohan’s present age.

(iv) A train travels a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, then it would have taken 3 hours more to cover the same distance. We need to find the speed of the train.

Solution:
(i) Let Breadth of rectangular plot = x m
Length of rectangular plot= (2x + 1) m
∴ Area of rectangular plot = [x (2x + 1)] m² = (2x² + x) m²
According to question,
2x² + x = 528
S = 1
P = -528 × 2 = -1056
0r 2x² + x – 528 = 0
Or 2x² – 32x + 33x – 528 = 0
Or 2x(x – 16) + 33(x – 16) = 0
Or (x – 16) (2x + 33) = 0
Either x – 16 = 0 Or 2x + 33 = 0
x = 16 Or x = 2
∵ breadth of any rectangle cannot be negative, so we reject x = \(\frac{-33}{2}\), x = 16
Hence, breadth of rectangular plot = 16 m
Length of rectangular plot = (2 ×16 + 1)m = 33m
and given problem in the form of Quadratic Equation are 2x² + x – 528 = 0.

(ii) Let two consecutive positive integers are x and x + 1.
Product of Integers = x (x + 1) = x² + x
According to question,
Or x² + x – 306 = 0
S = 1, P = – 306
Or x² + 18x – 17x – 306 = 0
Or x(x + 18) -17 (x + 18) = 0
Or (x + 18) (x – 17) = 0
Either x + 18 = 0 Or x – 17 = 0
x = -18 Or x = 17
∵ We are to study about the positive integers, so we reject x = – 18.
x = 17
Hence, two consecutive positive integers are 17, 17 + 1 = 18
and given problem in the form of Quadratic Equation is x² + x – 306 = 0.

(iii) Let present age of Rohan = x years
Rohan’s mother’s age = (x + 26) years
After 3 years, Rohan’s age = (x + 3) years
Rohan’s mother’s age = (x + 26 + 3) years = (x + 29) years
∴ Their product = (x + 3) (x + 29)
= x² + 29x + 3x + 87
= x² + 32x + 87
According to question,
x² + 32x + 87 = 360
Or x² + 32x + 87 – 360 = 0
Or x² + 32x – 273 = 0
Or x² + 39x – 7x – 273 = 0
S = 32, P = – 273
Or x(x + 39) – 7(x + 39) = 0
Or (x + 39) (x – 7) =
Either x + 39 = Or x – 7 = 0
x = -39 Or x = 7
∵ age of any person cannot be negative so, we reject x = -39
∴ x = 7
Hence, Rohans present age = 7 years
and given problem in the form of Quadratic Equation is x² + 32x – 273 = 0.

(iv) Let u km/hour be the speed of train.
Distance covered by train = 480 km
Time taken by train = \(\frac{480}{u}\) hour
[ Using, Speed = \(\frac{\text { Distance }}{\text { Time }}\)
or Time = \(=\frac{\text { Distance }}{\text { Speed }}\) ]

If speed of train be decreased 8km/hr.
∴ New speed of train = (u – 8) km/hr.
and time taken by train = \(\frac{480}{u-8}\) hour
According to question.

or 3840 = 3 (u² – 8u)
or u² – 8u = 1280
or u² – 8u – 1280=0
or u² – 40u + 32u – 1280 = 0
S = -8, P = – 1280
or u(u – 40) + 32 (u – 40) = 0
or (u – 40)(u + 32) = 0
Either u – 40 = 0
or u + 32 = 0
u = 40 or u = -32
But, speed cannot be negative so we reject
u = – 32
∴ u = 40.
Hence speed of train is 40 km/hr Ans.