Trevor's older brother was twice his age 20 years ago. How old was Trevor a decade ago if his brother is now 32 years old?
If Trevor's brother is 32 years old today then 20 years ago he was = 32-20 = <T>subtract(32, 20)=12 years old
If Trevor's brother was 12 years old and he was twice Trevor's age, then Trevor was 12/2 = <T>divide(12, 2)=6.0 years old
If Trevor was 6 years old 20 years ago, then he must be 6 + 20 = <T>add(6, 20)=26 years old today
If Trevor is 26 years old today then a decade ago he must have been 26-10 = <T>subtract(26, 10)=16 years old
