Rick set out on his bike for a cookout at church, traveling at 10 mi/hr. Fifteen minutes later his mother, realizing that he had forgotten the hot dogs he signed up to bring, set out in the car to catch him. If she drove 40 mi/hr, how long did it take her to catch up with him? possible answers:
o 5 minutes
o 7.2 minutes
o 10 minutes
o 20 minutes
o 30 minutes
o none of the above