Explanation for answer of question No 28 in PA Test 2010

28. Three runners Ajay , Bharath and Charan run a race with Ajay finishing 20 meters ahead of Bharath and 34 ahead of Charan , while Bharath finishes 21 meters ahead of Charan . Each runner travels the entire distance at a constant speed. What was the length of the race?

A. 40 meters B. 50 meters C. 60 Meters D. 70 meters

Correct Answer: C

14 m 20 M

C<---------------àB<------------------àA

This is what the race looks like when A reaches the end. Notice that B has already created a distance of 14 m between himself and C. When B reaches the end point, ie. after another 20 m, distance between him and C is 21 m i.e. another 7 m.

21 M

<------------------------------------à

_____________________________________

C B

So in every 20 m B is creating a distance of 7 m between himself and C. To create a distance of 21 m between himself and C, he must have run a total of 60m. The race must be of 60 m.