Question

The ratio of the ages of a father and his son is 17:7, respectively. Six years ago, the ratio of their age was 3:1, respectively. Find the present age of the son. RRB NTPC (Phase-1) 2016 (1) 21 yr (2) 7 yr (3) 14 yr (4) 28 yr

11th - 12th Class

Maths

Solution

4.0 (1 ratings)

3. (1) Let the ages of the father and the son be ( 17 x ) and ( 7 x, ) respectively. According to the question, [ begin{aligned} & frac{17 x-6}{7 x-6}=frac{3}{1} Rightarrow quad & 17 x-6=21 x-18 end{aligned} ] ( Rightarrow quad 21 x-17 x=18-6 ) ( Rightarrow quad 4 x=12 Rightarrow x=3 ) Thus, present age of the son ( =7 x=7 times 3=21 mathrm{yr} )