physics problem?

Question

Two hoses, one of 2.0cm diameter, the other of 1.0cm diameter are connected one behind the other to a faucet. At the open end of the hose, the flow of water measures 1.0L/min. Through which pipe does the water flow faster?

Answer 1

The same volume of water must pass through both hoses, therefore the velocity of water must be faster in the smaller hose. In fact, the velocity is inversely proportional to the square of the diameter (i.e. the cross-sectional area), so that the water velocity in the smaller hose will be 4 times that of the larger hose.