<PRE><B>Question 448309</B>
Filling the tank  		1 job					
Pipe I	6	hours					
It does   1/ 6	jobs in 1	minute				
Pipe II	8	hours					
It does   1/ 8	of thejob in 1 	minute				
Pipe III	12	hours					
It does  1/9	of the job in 1 	minute				
							
Together they will do 	 1/ 6+  1/ 8++1/12
Together they will do   7/24of the job in one hour
So they will take 3 3/7	hours				
				
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