Question

A girl is twice as old as her sister. Five years hence, the product of their ages (in years) will be 375. Find their present ages.

Answer 1

Let the age of the girl be = 2y years

Her sister’s age is = y years

(2y + 5)(y + 5) = 375

2y² + 5y+ 10y + 25 – 375 = 0

2y² + 15y – 350 = 0

y = 10, y cannot be (-ve).

∴ Girls age is 2y = 20 years.

Her sister’s age = y = 10 years.