Aman's age is 3 times his son's age. Ten years ago he was five times his son's age. Find their present ages.

Let Aman's present age be A and his son's present age be S.

According to the first condition, Aman's age is 3 times his son's age:
A = 3S (Equation 1)

Ten years ago, Aman's age was A - 10 and his son's age was S - 10. According to the second condition, Aman was five times his son's age:
A - 10 = 5(S - 10) (Equation 2)

Now we can solve these two equations simultaneously. Substitute Equation 1 into Equation 2:
3S - 10 = 5(S - 10)
3S - 10 = 5S - 50
50 - 10 = 5S - 3S
40 = 2S
S = 20

Now substitute the value of S (son's age) back into Equation 1 to find Aman's age:
A = 3S
A = 3 * 20
A = 60

Therefore, Aman's present age is 60 years and his son's present age is 20 years.