Answer:
this is the answer b
Explanation:
Let the present ages of Father and son be 4x and x (Given in the question). 5 years ago means (-5 from the present age).
F/S=4x/x [Equation 1]
Given 5 years ago the age of Father and son was 7y : y .
This implies,
(F-5)/(S-5) =7y/y [equation 2]
Sub 1 in 2,
(4x-5x)/(x-5)=7y/y (y gets cancelled)
4x-5=7x-35
35–5=7x-4x
30=3x
X=10
Present age F and son are 40 and 10.