The sum of the present ages of a father and his son is 126 years. 8 years ago their respective ages were in the ratio of 7 : 4. After 7 years what will be the ratio of ages of father and son?

Sum of the present ages of a father and his son = 126 years

Sum of their ages 8 years ago = $$126-8(2)=110$$ years

=> Father's age at that time = $$\frac{7}{(7+4)}\times110=70$$ years

=> Son's age at that time = $$110-70=40$$ years

Thus, present age of father = $$70+8=78$$ years

=> Son's present age = $$40+8=48$$ years

$$\therefore$$ Ratio of ages of father and son after 7 years = $$\frac{78+7}{48+7}=\frac{85}{55}$$

= $$17:11$$

=> Ans - (B)