Math
posted by nick .
A truck traveling at an average rate of 45 miles per hour leaves a rest stop. Fifteen minutes later a car traveling at an average rate of 60 miles per hour leaves the same rest stop traveling the same route. How long will it take for the car to catch up with the truck?

miles truck drove before car left rest stop = 45 * 1/4
miles an hour at which the car is catching up : 6045 = 15 mph
how long to drive 45/4 miles at 15 mph?