Carcass wrote:
Mary passed a certain gas station on a highway while traveling west at a constant speed of 50 miles per hour. Then, 15 minutes later, Paul passed the same gas station while traveling west at a constant speed of 60 miles per hour. If both drivers maintained their speeds and both remained on the highway for at least 2 hours, how long after he passed the gas station did Paul catch up with Mary?
A. 30 min
B. 45 min
C. 1 hr
D. 1 hr 15 min
E. 1 hr 30 min
Mary passes gas station and travels at 50 mph for 15 minutesSo, Mary drove for 1/4 hours
Distance traveled = (time)(speed)
= (1/4)(50)
= 50/4
=
12.5 milesPaul passes the same gas station and travels at 60 mph IMPORTANT: At this point, Paul is
12.5 miles behind Mary.
However, since Paul is traveling 10 mph FASTER than Mary, the gap between them SHRINKS at a rate of
10 mph.
So, at this point, we need to determine the time it takes for the
12.5 mile gap to shrink to zero.
Time = (distance)/(speed)
=
12.5/
10= 1.25 hours
= 1 hour 15 mins
= D
Cheers,
Brent