Problem: the length of the bridge , which a train 130 metres long and travelling at 36 km / hr can cross in 45 seconds , is :
Rationale: "speed = [ 36 x 5 / 18 ] m / sec = 10 m / sec time = 45 sec let the length of bridge be x metres . then , ( 130 + x ) / 45 = 10 = > 130 + x = 450 = > x = 320 m . answer : a"
annotated_formula: subtract(multiply(divide(multiply(36, speed(const_1000, const_1)), speed(const_3600, const_1)), 45), 130)