Question

The present age of Kalyani is 9 times her son's age. 11 years hence, the ratio of the ages of Kalyani and her son will be 12 : 5. Find the present age of Kalyani.
1. 21 yrs
2. 25 yrs
3. 20 yrs
4. Could not be determined
5. None of the above

Answer 1

Correct Answer - Option 1 : 21 yrs

Given:

Present age of Kalyani is 9 times her son’s age.

11 years hence, the ratio of the ages of Kalyani and her son = 12 : 5

Calculation:

Let the present age of son be x

⇒ Present age of Kalyani be 9x

⇒ (x + 11)/(9x + 11) = 5/12

⇒ 12(x + 11) = 5(9x + 11)

⇒ 12x + 132 = 45x + 55

⇒ 45x – 12x = 132 – 55

⇒ 33x = 77

⇒ x = 77/33

⇒ x = 7/3

Present age of Kalyani = 9 × (7/3) years

⇒ 21 years

∴ Present age of Kalyani is 21 years