The product of Ramu's age (in years) five years ago and his age(in years)nine years later is 15. Determine Ramu's present age.

Ramu's present age = x years
Ramu's age five years ago = (x - 5) years
Ramu's age nine years later = (x + 9) years
Condition: Product of Ramu's age five years ago and his age nine years later is 15.
(x - 5)(x + 9) = 15
x ² + 4x - 45 = 15
x ² + 4x - 45 - 15 = 0
x ² + 4x - 60 = 0
x ² + 10x - 6x - 60 = 0
x(x + 10) - 6(x + 10) = 0
(x + 10)(x - 6) = 0
x = -10 or x = 6
∴ Ramu's present age is 6 years
Checking:
Ramu's age five years ago = (6 - 5) year = 1 year
Ramu's age nine years later = (6 + 9) years = 15 years
Checking:
1(15) = 15.