Party A and Party B start from place A and drive in the same direction. Party A travels 36 kilometers per hour and Party B travels 48 kilometers per hour. If Party A leaves 2 hours earlier than Party B, how long will it take Party B to catch up with Party A?

Solution: distance difference = 36× 2 = 72km.

Speed difference = 48-36 = 12km/h

B needs 72/ 12=6 hours to catch up with A.