At the end of spring break, lucy left the beach and drove back towards home, driving at a rate of 40 mph. lucy's friend left the beach for home 30 minutes (half an hour) later, and drove 50 mph. how long, in hours, did it take lucy's friend to catch up to lucy?
Accepted Solution
A:
Lucy's friend makes up for Lucy's 20-mile head start at the rate of 10 miles per hour. Lucy's friend will catch up with Lucy after (20 mi)/(10 mi/h) = 2 hours.