The ratio of a man's age and his son's age is 7 : 3 and the product of their ages is 756. The ratio of their ages after 10 years will be-

Question: The ratio of a man's age and his son's age is 7 : 3 and the product of their ages is 756. The ratio of their ages after 10 years will be-

Solution:
let, man's age is 7x and son's age is 3x

So,
7x × 3x = 756
⇒ 21x² = 756
⇒ x² = 36
∴ x = 6

After 10 years, father's age will be 42 + 10 = 52 year
After 10 years, son's age will be 18+ 10 = 28 year
Ratio = 52 : 28
= 13 : 7