Question 70
The sum of the present ages of a father and his son is 99 years. When the father was as old as his son is now, his age was four times the age of the son at that time. The ratio of the present ages of the son and the father is
Solution
Let son's present age = $$x$$ years and father's present age = $$y$$ years
=> $$x+y=99$$
Let $$n$$ years ago, father was same as his son's age, where $$n=y-x$$
=> $$4(x-n)=(y-n)$$
=> $$4x-4(y-x)=y-y+x$$
=> $$8x-4y=x$$
=> $$7x=4y$$
=> $$\frac{x}{y}=\frac{4}{7}$$
=> Ans - (D)
