To round to the thousands, you have to loook at the number before it in the hundredths place, if it's above 5 you round up, if it's not you keep it the same and replace digits with 0s. Since 0 is less than 5, than roudned to the thousands is 42,000 Hpe this helped!
It would take the faucet 18 hours to fill the tank because 18/12=1.5. That means it will be 1.5 times slower to fill the tank up with the hose on. 1.5*12=18.
