how long does a train 110 m long running at the speed of 72 km / hr takes to cross a bridge 140 m length ?
"speed = 72 * 5 / 18 = 20 m / sec total distance covered = 110 + 140 = 250 m . required time = 250 / 20 = 12.5 sec . answer : b"
divide(add(110, 140), multiply(72, const_0_2778))