a man rows his boat 120 km downstream and 60 km upstream , taking 2 hours each time . find the speed of the stream ?
"speed downstream = d / t = 120 / ( 2 ) = 60 kmph speed upstream = d / t = 60 / ( 2 ) = 30 kmph the speed of the stream = ( 60 - 30 ) / 2 = 15 kmph answer : b"
divide(subtract(divide(120, 2), divide(60, 2)), const_2)