Question

Five year hence, the age of jacob will be three times that of his son. Five years ago, jacob age was seven times that of his son. What are their present age ?

Answer 1

Let x be the present age of Jacobs son and y be the present age of Jacob. 5 year hence it has relation :

(y + 5) = 3(x + 5)

y + 5 = 3x + 15

3x - y + 10 = 0 ............... (Eqn 1)

5 years ago it has relation :-

(y - 5) = 7(x - 5)

7x - y - 30 = 0 ............ (Eqn 2)

From Equation 1

Y = 3x + 10 .......... (Eqn 3)

On substituting the value of y in Eqn. 2 we get :-

7x – (3x + 10) – 30 = 0

4x – 40 = 0

x = 10

On substituting x = 10 in eqn 3

y = 3 × 10 + 10

y = 40

Hence the present age of Jacob = 40 years and son age = 10 years