Question

Five years ago a man was seven times as old as his son. Five years hence, the father will be 3 times as old as his son. Find their present ages.

Answer 1

Let the age of the son five years ago = x
Therefore, the age of the man = 7x
The present age of the son = x+5
The present age of the man = 7x+5
The age of the son after 5 years = x+5+5=x+10
The age of father after 5 years = 7x+5+5=7x+10
According to the question
7x+10=3(x+10)
7x+10=3x+30
7x-3x=30-10
4x=20
x=20÷4=5
Therefore, the present age of
the son=x+5=5+5=10 years
father=7x+5=7×5+5=40 years