Two women started running simultaneously around a circular track of length 1800 m from the same point at speeds of 10 km/hr and 20 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 choices
A) 72  B) 74  C) 76  D) 78  E) 80

Rationale: time taken to meet for the first time anywhere on the track = length of the track / relative speed = 1800 / ( 30 + 60 ) 5 / 18 = 1800 * 18 / 90 * 5 = 72 seconds . answer : a
Answer: A