Father is 3 times as old as his son. After 12 years, he will be twice as old as his son. Find the son’s present age.

Explanation

• Let son's age = x, father's age = 3x
• After 12 years: 3x + 12 = 2(x + 12)
• Solving: 3x + 12 = 2x + 24
• x = 12
• Son's present age = 12 years