Question

Carolyn leaves at 2:15 and drives 40 miles per hour. Marcel leaves at 2:45 and drives at 65 miles per hour. If they are traveling the same route, at what time will Marcel pull ahead of Carolyn?

Answer 1

Marcel leaves 30 minutes after Carolyn, leaving between them a gap of 40mph*0.5h=20miles
To catch up with the 20miles, Marcel uses the extra (65-40=25)mph that he has.
Therefore 20m/25mph=0.8h=0.8*60min=48minutes after 2:45, which is at 3:33, Marcel catches up to Carolyn.