The swimming pool can be filled in 40 hours using the medium hose. With the large hose, it will take 20 hours instead. If we use both hoses (without any impact on waterflow rate), how long does it take to fill the pool? Round your answer to the nearest hour.
1 pool / ( 1/40 + 1/20) = 1/ ( 1/40 + 2/40 ) = 40/3 hours Simplify if you need......