Two persons are to run a race, but one can run 11 meters per second, whereas the other can run 5 meters per second. If the slower runner has a 72-meter head start, how long will it be before the faster runner catches the slower runner, if they begin at the same time?
A) 10.5 sec
B) 12 sec
C) 11.5 sec
D) 13 sec
E) 14.40 sec

Question

Two persons are to run a race, but one can run 11 meters per second, whereas the other can run 5 meters per second. If the slower runner has a 72-meter head start, how long will it be before the faster runner catches the slower runner, if they begin at the same time? ​
A) 10.5 sec
B) 12 sec
C) 11.5 sec
D) 13 sec
E) 14.40 sec

Quizplus · Accepted Answer

Let t be the time taken by the faster runner to catch up with the slower runner.
Distance covered by slower runner in t seconds = 5t + 72 meters
Distance covered by faster runner in t seconds = 11t meters
Since they meet, both runners cover the same distance.
5t + 72 = 11t
6t = 72
t = 12 seconds.

Two Persons Are to Run a Race, but One Can