Two trains running in opposite directions cross a man standing on the platform in 20 seconds and 18 seconds respectively and they cross each other in 19 seconds. The ratio of their speeds is:
Choose the correct choice:
A) 1 : 1
B) 3 : 2
C) 3 : 8
D) 3 : 25
E) 3 : 4

Rationale: "let the speeds of the two trains be x m / sec and y m / sec respectively . then , length of the first train = 20 x meters , and length of the second train = 18 y meters . ( 20 x + 15 y ) / ( x + y ) = 19 = = > 20 x + 18 y = 19 x + 19 y = = > x = y = = > x / y = 1 / 1 answer : option a"
Answer: A