Bunuel wrote:
In a 4000 meter race around a circular stadium having a circumference of 1000 meters, the fastest runner and the slowest runner reach the same point at the end of the 5th minute, for the first time after the start of the race. All the runners have the same starting point and each runner maintains a uniform speed throughout the race. If the fastest runner runs at twice the speed of the slowest runner, what is the time taken by the fastest runner to finish the race?
(A) 20 min
(B) 15 min
(C) 10 min
(D) 5 min
(E) 3 min
Are You Up For the Challenge: 700 Level QuestionsWe know,
circular track = 1000 mtrs.
race = 4000 mtrs.
According to the question, after 5th minute both, slow and the fast runner meet at the starting point.
Slow runner's speed= 1000/5 = 200 mtrs./min
Fast runner's speed = 200 * 2 = 400 mtrs./min
In the 5th min., fast runner has covered = 400*5 = 2000 mtrs.
In the 5th min., slow runner has covered = 200*5 = 1000 mtrs.
If it took 5 mins., to complete 2000 mtrs., it will take another 5 mins to complete 4000 mtrs.
Thus, total of 10 mins to finish the race.
The correct option is C.