a man can row a boat at 10 kmph in still water and the speed of the stream is 8 kmph . what is then time taken to row a distance of 90 km down the stream ?
speed in down stream = 10 + 8 = 18 time taken to cover 90 km down stream = 90 / 18 = 5 hrs . answer : b
divide(90, add(10, 8))