If it takes one hour to fill a pool with 50 ft^3 of water, how many hours will it take to fill a pool that measures 10 ft by 8 ft with a depth of 5 ft?
Your second pool has a volume of (10 ft)*(8 ft)*(5 ft) = 400 ft^3, which is 8 times 50 ft^3. It can be expected to take 8 times as long to fill, so 8 hours.
