A train overtakes two girls who are walking in the opposite direction in which the train is going at the rate of 3 km/h and 6km/h and passes them completely in 36 seconds and 30 seconds respectively. The length of the train is:	Choose the correct choice from the following answers:
A) 120m  B) 150m  C) 125m  D) None of these  E) Cannot be determined
Explanation:   Let the length of the train e x meter, and let the speed of train be y km/h, then   x = (y + 3)5/18 × 36 .........(1)   and x = (y + 6)5/18 × 30 .....(2)   From eq (1) and (2), we get   (y + 3) × 36 = (y + 6) × 30   y = 12 km/h   x = (y + 3) × 5/18 × 36   x = 150 m   Answer: 150m
<result>B</result>
A train overtakes two girls who are walking in the opposite direction in which the train is going at the rate of 3 km/h and 6km/h and passes them completely in 36 seconds and 30 seconds respectively. The length of the train is: