Problem: two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 25 seconds . the ratio of their speeds is ?
Rationale: "let the speeds of the two trains be x m / sec and y m / sec respectively . then , length of the first train = 27 x meters , and length of the second train = 17 y meters . ( 27 x + 17 y ) / ( x + y ) = 25 = = > 27 x + 17 y = 25 x + 25 y = = > 2 x = 8 y = = > x / y = 4 / 1 . answer : b"
annotated_formula: divide(subtract(27, 25), subtract(25, 17))