A tank can be filled by pipe A in 2 hours and pipe B in

A tank can be filled by pipe A in 2 hours and pipe B in 6 hours. At 10 A.M. pipe A was opened. At what time will the tank be filled if pipe B is opened at 11 A.M.?

From the given question ,

Part of the tank filled in 1 hour by pipe A =	1
	2

Part of the tank filled by both pipes in 1 hour =	1	+	1	=	3 + 1	=	2
	2		6		6		3

So, Time taken to fill 2 /3 part = 60 minutes

∴ Time taken to fill	1	part	=	60 × 3	×	1	= 45 minutes
	2			2		2

∴ The tank will be filled at 11 : 45 A.M.