Two persons start running simultaneously around a circular track of length 600 m from the same point at speeds of 20 km/hr and 10 km/hr. When will they meet for the first time any where on the track if they are moving in opposite directions ? Choose the correct choice from the following answers.
A) 27 sec B) 87 sec C) 67 sec D) 72 sec E) 37 sec
Explanation:   Time taken to meet for the first time anywhere on the track   = length of the track / relative speed   = 600 / (20 + 10)5/18 = 600 x 18 / 30 x 5 = 72 seconds.   Answer: 72 sec
<result>D</result>
Two persons start running simultaneously around a circular track of length 600 m from the same point at speeds of 20 km/hr and 10 km/hr. When will they meet for the first time any where on the track if they are moving in opposite directions ?