a train covers a distance of 12 km in 16 min . if it takes 6 sec to pass a telegraph post , then the length of the train is ?
"speed = ( 12 / 16 * 60 ) km / hr = ( 45 * 5 / 18 ) m / sec = 12.5 m / sec . length of the train = 12.5 * 6 = 75 m . answer : d"
divide(12, subtract(divide(12, 16), 6))