Problem: a train running at the speed of 50 km / hr crosses a post in 4 seconds . what is the length of the train ?
Rationale: "speed = ( 54 x 5 / 18 ) = 15 m / sec . length of the train = ( speed x time ) . length of the train = 15 x 4 m = 60 m . answer : c"
annotated_formula: multiply(divide(multiply(50, const_1000), const_3600), 4)