a train passes a station platform in 50 sec and a man standing on the platform in 20 sec . if the speed of the train is 72 km / hr . what is the length of the platform ?
"speed = 72 * 5 / 18 = 20 m / sec . length of the train = 20 * 20 = 400 m . let the length of the platform be x m . then , ( x + 400 ) / 50 = 20 = > x = 600 m . answer : d"
multiply(20, multiply(72, const_0_2778))