lena bought a saltwater fish tank that holds 400 gallons of water. she started filling the tank on friday, but then stopped after putting only 70 gallons of water in the tank. on saturday, she bought a bigger hose and began filling the tank again. it took her 1 hour and 50 minutes on saturday to completely fill the tank. which equation represents the number of gallons of water in the fish tank on saturday, given the amount of time in minutes that lena spent filling the tank?