Question

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. 

Answer 1

Let the present age of Ramu be x years

So, 9 years later, the age of him = (x + 9) years

And, five years ago, his age = (x – 5) years

Given relationship between the ages can be expressed as:

(x – 5)(x + 5) = 15

x² + 9x – 5x – 45 = 15

x² + 4x – 45 – 15 = 0

x² + 4x – 60 = 0

x² – 6x + 10x – 60 = 0 [By factorisation method]

x(x – 6) + 10(x – 6) = 0

(x – 6)(x + 10) = 0

x = 6  or  x = – 10(neglected) as the age can be never be negative.

Hence, the present age of Ramu is 6 years.