The task is to generate the correct answer for a given math problem.

[EX Q]: Problem: two trains travel in opposite directions at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 12 seconds . the length of the faster train is
[EX A]: 270 m

[EX Q]: Problem: when the price of a product was decreased by 20 % , the number sold increased by 60 % . what was the effect on the total revenue ?
[EX A]: 28 %

[EX Q]: Problem: a train which has 390 m long , is running 45 kmph . in what time will it cross a person moving at 9 kmph in same direction ?
[EX A]:
39 sec