A vampire drains three people a week. His best friend is a werewolf who eats five people a week, but only fresh ones, never drained ones. How many weeks will a village of 72 people last them both?
The vampire and werewolf need 3 + 5 = <T>add(3, 5)=8 people a week.
A village of 72 people will last them both 72 / 8 = <T>divide(72, 8)=9.0 weeks.
