how long does a train 100 m long running at the speed of 65 km / hr takes to cross a bridge 145 m length ?
"speed = 65 * 5 / 18 = 18 m / sec total distance covered = 100 + 145 = 245 m . required time = 245 / 18 = 13.6 sec . answer : a"
divide(add(100, 145), multiply(65, const_0_2778))