Haider is 3 times as old as his son. After 10 years, the sum of their ages will be 76 years. Find Haider's present age.

39 years

42 years

45 years

None of these

Let Haider's son's present age be x.

Haider's present age = 3x

After 10 years:

Son's age = x + 10

Haider's age = 3x + 10

The sum of their ages after 10 years will be 76:

x + 10 + 3x + 10 = 76

4x + 20 = 76

4x = 56

x = 14

Haider's present age = 3x = 3 × 14 = 42