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?	Choose the correct option.
A) 20 min B) 15 min C) 10 min D) 5 min E) None of these
Explanation :   The ratios of the speed of the fastest and the slowest is 2 : 1. Hence, they should meet only at one point at the circumference i.e the starting point (As the difference in the ratios in reduced form is 1).   For the two of them to meet for the first time, the faster shuld have completed one complete round over the slower one. Since, the two of them meet for the first time after 5 min, the faster one should have completed 2 rounds (i.e 2000 m) and the slower one should have completed 1 round (1000 in this time).   Thus the faster one would complete the race ( i.e 4000 m) in 10 min.   Answer : 10 min
<result>C</result>
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?