Selina Textbook Solutions: Proportion | Mathematics Class 6 ICSE PDF Download

 Page 1


EXERCISE 12(A) 
Question 1. 
In each of the following, check whether or not the given ratios form a proportion : 
(i) 8 : 16 and 12 : 15 
(ii) 16 : 28 and 24 : 42 
(iii) 12 ÷ 3 and 8 ÷ 2 
(iv) 25 : 40 and 20 : 32 
(v)  
(vi)  and 14 : 16 
Solution: 
Page 2


EXERCISE 12(A) 
Question 1. 
In each of the following, check whether or not the given ratios form a proportion : 
(i) 8 : 16 and 12 : 15 
(ii) 16 : 28 and 24 : 42 
(iii) 12 ÷ 3 and 8 ÷ 2 
(iv) 25 : 40 and 20 : 32 
(v)  
(vi)  and 14 : 16 
Solution: 
 
Question 2. 
Find the value of x in .each of the following proportions : 
(i) x : 4 = 6 : 8 
(ii) 14 : x = 7 : 9 
(iii) 4 : 6 = x : 18 
(iv) 8 : 10 = x : 25 
(v) 5 : 15 = 4 : x 
(vi) 16 : 24 = 6 : x 
Solution: 
Page 3


EXERCISE 12(A) 
Question 1. 
In each of the following, check whether or not the given ratios form a proportion : 
(i) 8 : 16 and 12 : 15 
(ii) 16 : 28 and 24 : 42 
(iii) 12 ÷ 3 and 8 ÷ 2 
(iv) 25 : 40 and 20 : 32 
(v)  
(vi)  and 14 : 16 
Solution: 
 
Question 2. 
Find the value of x in .each of the following proportions : 
(i) x : 4 = 6 : 8 
(ii) 14 : x = 7 : 9 
(iii) 4 : 6 = x : 18 
(iv) 8 : 10 = x : 25 
(v) 5 : 15 = 4 : x 
(vi) 16 : 24 = 6 : x 
Solution: 
 
 
Question 3. 
Find the value of x so that the given four numbers are in proportion : 
(i) x, 6, 10 and 15 
(ii) x, 4, 15 and 30 
(iii) 2, x, 10 and 25 
(iv) 4, x, 6 and 18 
(v) 9, 12, x and 8 
(vi) 4, 10, 36 and x 
(vii) 7, 21, x and 45 
(viii) 6, 8, 12 and x. 
Solution: 
Page 4


EXERCISE 12(A) 
Question 1. 
In each of the following, check whether or not the given ratios form a proportion : 
(i) 8 : 16 and 12 : 15 
(ii) 16 : 28 and 24 : 42 
(iii) 12 ÷ 3 and 8 ÷ 2 
(iv) 25 : 40 and 20 : 32 
(v)  
(vi)  and 14 : 16 
Solution: 
 
Question 2. 
Find the value of x in .each of the following proportions : 
(i) x : 4 = 6 : 8 
(ii) 14 : x = 7 : 9 
(iii) 4 : 6 = x : 18 
(iv) 8 : 10 = x : 25 
(v) 5 : 15 = 4 : x 
(vi) 16 : 24 = 6 : x 
Solution: 
 
 
Question 3. 
Find the value of x so that the given four numbers are in proportion : 
(i) x, 6, 10 and 15 
(ii) x, 4, 15 and 30 
(iii) 2, x, 10 and 25 
(iv) 4, x, 6 and 18 
(v) 9, 12, x and 8 
(vi) 4, 10, 36 and x 
(vii) 7, 21, x and 45 
(viii) 6, 8, 12 and x. 
Solution: 
 
 
Question 4. 
The first, second and the fourth terms of a proportion are 6, 18 and 75, respectively. 
Find its third term. 
Solution: 
Let the third term = x 
6 : 18 : : x : 75 
= 18 x x = 6 x 75 
x =  = 25 
The third term of proportion is 25 
Page 5


EXERCISE 12(A) 
Question 1. 
In each of the following, check whether or not the given ratios form a proportion : 
(i) 8 : 16 and 12 : 15 
(ii) 16 : 28 and 24 : 42 
(iii) 12 ÷ 3 and 8 ÷ 2 
(iv) 25 : 40 and 20 : 32 
(v)  
(vi)  and 14 : 16 
Solution: 
 
Question 2. 
Find the value of x in .each of the following proportions : 
(i) x : 4 = 6 : 8 
(ii) 14 : x = 7 : 9 
(iii) 4 : 6 = x : 18 
(iv) 8 : 10 = x : 25 
(v) 5 : 15 = 4 : x 
(vi) 16 : 24 = 6 : x 
Solution: 
 
 
Question 3. 
Find the value of x so that the given four numbers are in proportion : 
(i) x, 6, 10 and 15 
(ii) x, 4, 15 and 30 
(iii) 2, x, 10 and 25 
(iv) 4, x, 6 and 18 
(v) 9, 12, x and 8 
(vi) 4, 10, 36 and x 
(vii) 7, 21, x and 45 
(viii) 6, 8, 12 and x. 
Solution: 
 
 
Question 4. 
The first, second and the fourth terms of a proportion are 6, 18 and 75, respectively. 
Find its third term. 
Solution: 
Let the third term = x 
6 : 18 : : x : 75 
= 18 x x = 6 x 75 
x =  = 25 
The third term of proportion is 25 
Question 5. 
Find the second term of the proportion whose first, third and fourth terms are 9, 8 and 
24 respectively. 
Solution: 
Let the second term = x 
9 : x : : 8 : 24 
=> x x 8 = 24 x 9 
x =  = 3 x 9 = 27 
The second term of proportion = 27 
Question 6. 
Find the fourth term of the proportion whose first, second and third terms are 18, 27, 
and 32 respectively. 
Solution: 
Let the fourth term = x 
18 : 27 : : 32 : x 
=> 18 x x = 27 x 32 
=> x =  = 3 x 16 = 48 
Fourth term = 48 
Question 7. 
The ratio of the length and the width of a school ground is 5 : 2. Find the length, if the 
width is 40 metres. 
Solution: 
Let the length = x m, 
width = 40 m 
The ratio of length to width = x : 40 
as per given statement 5 : 2 = x : 40 
=> 2 x x = 40 x 5 
x =  = 20 x 5 = 100 m 
Question 8. 
The ratio of the sale of eggs on a Sunday and that of the whole week at a grocery shop 
was 2 : 9. If the total value of the sale of eggs in the same week was Rs 360, find the 
value of the sale of eggs that Sunday. 
Solution: 
Let, the sale of eggs on Sunday = x 
Sale in week = Rs 360 
According to question, 2 : 9 = x : 360 
=> 9 x x = 360 x 2 
x =  = Rs 80 
Sale on Sunday = Rs 80