John is half times younger than his father, who is 4 years older than John's mother. If John's father is 40 years old, what's the age difference between John and his mother?
What is the solution?
John is half times his father's age. Thus 1/2*40 = 20 years.
Since the mother is 4 years younger than the father, she is 40-4= 36 years old.
The age difference between John and his mother is 36-20 = 16 years