Question

5 years hence, the age of a man shall be 3 times the age of his son while 5 years earlier the age of the man was 7 times the age of his son.The present age of the man is

(a) 45 years (b) 50 years (c) 47 years (d) 40 years

Answer 1

Let the age of son 5 years earlier = x
So, age of father 5 years earlier = 7x

Now, present ages of son and father are x+5 and 7x+5.

5 years hence, age of son = x+10
5 years hence, age of father = 7x+10

Given 7x+10 = 3 $\times$ (x+10)
$\Rightarrow$7x+10 = 3x+30
$\Rightarrow$ 4x = 20
$\Rightarrow$ x = ​​​​​​​5

Hence, the present age of man is 7 $\times$ 5 + 5 = 40 years.