a train 420 m long is running at a speed of 48 km / hr . in what time will it pass a bridge 60 m long ?
"total length = 420 + 60 = 480 speed = 48 km / h = ( 48 * 5 ) / 18 = 40 / 3 m / s time = ( 480 * 3 ) / 40 = 36 sec . answer : b"
divide(420, multiply(subtract(48, 60), const_0_2778))