a man can row downstream at 25 kmph and upstream at 15 kmph . find the time to reach a destination point at a distance of 50 km along the downstream .
"let the speed of the man in downstream = 25 kmph . distance to be covered along the stream = 50 kmph = > time taken = d / s = 50 / 25 = 2 hrs . answer : d"
divide(divide(add(25, 15), const_2), const_2)