Question 579689
Emptying the pool is one job						
Faucet I	6	hours				
It does	  1/ 6	of the job in 1	hour			
Faucet II	3	hours				
It does	  1/ 3	of thejob in 1	hour			
Together they will do		  1/ 6	+	  1/ 3		
Together they will do	  1/ 2		of the job in one	hour

So in 2 hours they will complete emptying the pool