Pipe A can fill the tank in 50 minutes and pipe B in 40min and pipe C can empty the tank in 2 hours. How long it will take to fill the tank if three of the pipes are operating together?
Choose the correct answer:	A) 22.22	B) 27.27	C) 29.35	D) 31.2	E) 35.6
Pipe A fills 1/50th of the tank in a minute and pipe B, 1/40th. Pipe C empties in 120min(2 hours)   (1/50)+(1/40)-(1/120)=(1/x)   22/600=1/x =&gt; x=600/22 =&gt; x=27.27 minutes   Answer: 27.27
<result>B</result>
Pipe A can fill the tank in 50 minutes and pipe B in 40min and pipe C can empty the tank in 2 hours. How long it will take to fill the tank if three of the pipes are operating together?