a train traveling at 72 kmph crosses a platform in 30 seconds and a man standing on the platform in 20 seconds . what is the length of the platform in meters ?
"speed of the train in metres / sec = 72000 / 3600 = 20 distance travelled by train to cross the platform = 30 * 20 = 600 = length of train + length of platform distance travelled by train to cross the man = 20 * 20 = 400 = length of train length of platform = 600 - 400 = 200 answer : a"
subtract(multiply(divide(multiply(72, const_1000), const_3600), 30), multiply(divide(multiply(72, const_1000), const_3600), 20))