a train passes a platform in 18 seconds . the same train passes a man standing on the platform in 20 seconds . if the speed of the train is 54 km / hr , the length of the platform is
"speed of the train = 54 km / hr = ( 54 × 10 ) / 36 m / s = 15 m / s length of the train = speed × time taken to cross the man = 15 × 20 = 300 m let the length of the platform = l time taken to cross the platform = ( 300 + l ) / 15 = > ( 300 + l ) / 15 = 18 = > 300 + l = 15 × 18 = 270 = > l = 390 - 270 = 120 meter answer is a ."
multiply(multiply(const_0_2778, 54), subtract(18, 20))