Problem: how long does a train 125 m long running at the speed of 78 km / hr takes to cross a bridge 125 m length ?
Rationale: "speed = 78 * 5 / 18 = 21.7 m / sec total distance covered = 125 + 125 = 250 m . required time = 250 / 21.7 ' = 11.5 sec . answer : c"
annotated_formula: divide(add(125, 125), multiply(78, const_0_2778))