success1111 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

I solved this question by this way.

Distance Mary travelled by 15 minutes(catch up distance) is 50 * 15/60 = 12.5 miles

Paul catch up speed is 60-50 = 10.

Hour after Paul would catch up with mary is 12.5/10 = 1 hr 25 minutes.
I was surprised my answer was no there. Am i missing something? Please help

Pranay wrote:

success1111 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

I solved this question by this way.

Distance Mary travelled by 15 minutes(catch up distance) is 50 * 15/60 = 12.5 miles

Paul catch up speed is 60-50 = 10.

Hour after Paul would catch up with mary is 12.5/10 = 1 hr 25 minutes.
I was surprised my answer was no there. Am i missing something? Please help

1.25 hrs (as you calculated) is not equivalent to 1 hr 25 mins but it is 1 hr 15 mins.