a man rows his boat 90 km downstream and 55 km upstream , taking 3 hours each time . find the speed of the stream ?
"speed downstream = d / t = 90 / ( 3 ) = 30 kmph speed upstream = d / t = 55 / ( 3 ) = 18 kmph the speed of the stream = ( 30 - 18 ) / 2 = 6 kmph answer : b"
divide(subtract(divide(90, 3), divide(55, 3)), const_2)