Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively . If they cross each other in 22 seconds, what is the ratio of their speeds? Choose the correct choice from the following answers.
A) 1 : 1	B) 3 : 1	C) 2 : 3	D) 3 : 2	E) 3 : 4

Rationale: let the speed of the trains be x and y respectively length of train 1 = 27 x length of train 2 = 17 y relative speed = x + y time taken to cross each other = 22 s = ( 27 x + 17 y ) / ( x + y ) = 22 = ( 27 x + 17 y ) / = 22 ( x + y ) = 5 x = 5 y = x / y = 5 / 5 = 1 / 1 i . e 1 : 1 answer : a
Answer: A