Answer:
Let the age of Aman's son is x years.
So the age of Aman will be 3x years.
Ten years ago, the age of Aman's son = x - 10 and Aman's age = 3x - 10.
So according to question,
5(x - 10) = 3x - 10
or 5x - 50 = 3x - 10
Transposing 3x to the LHS and -50 to the RHS:
5x - 3x = -10 + 50 = 40
or 2x = 40
or x = 20
So Aman's age = 3x = 60 years and
Aman's son's age = x = 20 years.