Question

a woman is 7 times as old as her son after 5 years she will be 4 times as old as her son what are the present age of the mother and son

Answer 1

Let the present age of son = x years
therefore present age of woman = 7 x years

After 5 years
age of son = x+5 years
therefore age of mother = 4(x+5) = 4x + 20 years

Present age of woman = 7x
age of woman after 5 years = 7x+5 years

Therefore 
7x+5=4x+20
3x = 15
x = 5
The present age of son = 5 years
The present age of woman = 7*5 = 35 years

Answer 2

the present age of the son= 5 years
the present age of the mother= 35 years