Amount of water that the faucet leaks in 1 week = 42 gallons
That means
Amount of water that the faucet in Kali's house leaks in 7 days = 42 gallons
So
The amount of water that
the faucet in Kali's house leaks in 1 day = (42/7) gallons
= 6 gallons
Then
The amount of water that the
faucet in Kali's house leaks in 3 days = 6 * 3 gallons
= 18 gallons
So it can said from the above deduction that the amount of water leaked by the faucet in Kali's house is 18 gallons.