Question

5 years ago, the ratio of son and father was 6 ∶ 7 and After 5 years ratio becomes 11 ∶ 12. Find the present age of the son.

1. 20 years
2. 15 years
3. 19 years
4. 17 years
5. None of these

Answer 1

Correct Answer - Option 4 : 17 years

Given:

5 years ago age ratio of son and father = 6 ∶ 7

5 years after age ratio of son and father = 11 ∶ 12

Calculation:

Let the 5 years ago the age of son and father be 6x and 7x respectively

Now,

The total difference of age between son and father = 5 – (– 5)

⇒ 10 years

Now,

(6x + 10)/(7x + 10) = 11/12

⇒ 72x + 120 = 77x + 110

⇒ 120 – 110 = 77x – 72x

⇒ 5x = 10

⇒ x = 10/5

⇒ x = 2

Now,

The age of son 5 years ago = 6x

⇒ 6 × 2

⇒ 12 years

Now,

The present age of son = The Age of son 5years ago + 5

⇒ 12 + 5

⇒ 17

∴ The Present age of son will be 17 years.