Question

20. The ages of Sonal and Manoj are in the ratio 7:5. Ten years hence, the ratio of their ages
will be 9: 7. Find their present ages.
2. Five years ago a man was seven times as old as his son. Five years hence, the father will be
three times as old as his son Find thoi​

Answer 1

Solution :

1. The ages of Sonal and Manoj are in the ratio 7:5.

Let their ages be 7x and 5x respectively

After 10 years ; their ages are in the ratio of 9 : 7

> ( 7x + 10) / ( 5x + 10) = 9/7

> 45x + 90 = 49 x + 70

> 4x = 20

> x = 5

Age Of Sonal - 35 years

Age of Manoj - 25 years

2.

. Five years ago a man was seven times as old as his son.

Let the ages of the man and the son then be 7x and x

After 10 years ;

( 7x + 10 ) = 3( x + 10)

> 7x + 10 = 3x + 30

> 4x = 20

> x = 5

Age of father now :

> 40 years

Age of son now

> 10 years .

This is the required answer .

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Answer 2

Answer:

Answer (1)

Let the present ages be 7x and 5x. After 10 years

7x + 10/5x + 10 = 9/7

By Cross Multiplication

9(5x + 10) = 7(7x + 10)

45x + 90 = 49x + 70

49x - 45x = 90 - 70

4x = 20

x = 5

Present ages are :-

Sonal's age =7x = 7(5) = 35 years

Manoj's age = 5x = 5(5) = 25 years

$\rule{333}{2}$

Answer (2)

Let the age of son be x and father age be 7x

(7x + 10) = 3(10 + x)

7x + 10 = 30 + 3x

7x - 3x = 30 - 10

4x = 20

x = 5

Present ages are

Father = 40 years

Son = 10 years