a man rows his boat 84 km downstream and 60 km upstream , taking 4 hours each time . find the speed of the stream ?
"speed downstream = d / t = 84 / ( 4 ) = 21 kmph speed upstream = d / t = 60 / ( 4 ) = 15 kmph the speed of the stream = ( 21 - 15 ) / 2 = 3 kmph answer : e"
divide(subtract(divide(84, 4), divide(60, 4)), const_2)