a man rows his boat 72 km downstream and 30 km upstream , taking 3 hours each time . find the speed of the stream ?
"speed downstream = d / t = 72 / ( 3 ) = 24 kmph speed upstream = d / t = 30 / ( 3 ) = 10 kmph the speed of the stream = ( 24 - 10 ) / 2 = 7 kmph answer : e"
divide(subtract(divide(72, 3), divide(30, 3)), const_2)