This bunch of word problems will involve the cost and duration. Duration is a word which means more or less HOW LONG SOMETHING LASTS. For instance, consider the following problem.
Sue gets paid $4 per hour for raking leaves. How much will she get paid for raking leaves for 3 hours?
4 dollars per hour * 3 hours = 12 dollars
Jim gets paid $2 per hour for watering the grass. How much will he get paid for watering the grass for 2 hours?
2 dollars per hour * 2 hours = 4 dollars