Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?

Question

Accepted Answer

Part filled in 4 minutes = 4 ❨ 1 + 1 ❩ = 7

x =	❨	8	x 1 x 20	❩	= 10	2	min = 10 min. 40 sec.
		15				3

Remaining part =	❨	1 -	7	❩	=	8	.
			15			15

∴	1	:	8	:: 1 : x
	20		15

Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?

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