Daniel, my son, is exactly one fifth of my age. In 21 years time, I will be exactly twice his age. My wife is exactly seven times older than my daughter, Jessica. In 8 years time, my wife will be three times older then Jessica. How old are Daniel and Jessica now?

Answer

Daniel is 7 years old and Jessica is 4 years old.

Let x be the father’s age. So Daniel’s age is: x/5

In 21 years: 21 + x = 2(x/5 + 21)

Solving for x will give 35. Since Daniel’s age is x/5: 35/5 = 7

Let y be Jessica’s age. So mother’s age is: 7y

In 8 years: 7y + 8 = 3(y + 8)

Solving for y will give 4.