Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours. C is closed A and B can fill the remaining par in 7 hours. The number of hours taken by C alone to fill the tank is? Pick:	A) 76	B) 55	C) 14	D) 33	E) 99
Part filled in 2 hours = 2/6 = 1/3.   Remaining part = 1 - 1/3 = 2/3   (A + B)'s 1 hour work = 2/21   14's 1 hour work = [(A + B + 14)'s 1 hour work - (A + B)'s 1 hour work]   = (1/6 - 2/21) = 1/14   14 alone can fill the tank in 14 hours.Answer:14
<result>C</result>
Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours. C is closed A and B can fill the remaining par in 7 hours. The number of hours taken by C alone to fill the tank is?