how long does a train 100 m long running at the speed of 75 km / hr takes to cross a bridge 135 m length ?
"speed = 75 * 5 / 18 = 20.8 m / sec total distance covered = 100 + 135 = 235 m . required time = 235 / 20.8 ' = 11.3 sec . answer : a"
divide(add(100, 135), multiply(75, const_0_2778))