supposed 4.5 liters of water come out of a faucet each minute. for how many minutes was the faucet on if 48.6 of water came out?
First, analyze the dimensions. Note that you need to determine TIME (how many minutes?). If you divide "liters" by "[liters / minute]," you'll get "minutes."
Does that help you know whether to divide 4.5 liters per minute by 48.6 liters of water, or to divide 48.6 liters of water by 4.5 liters/minute?