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?	Select the correct option:
A) 17 hours B) 95 hours C) 14 hours D) 19 hours E) 18 hours
Part filled in 2 hours = 2/6 = 1/3.   Remaining part = 1 - 1/3 = 2/3   (A + B)'s 1 hour work = 2/21   C's 1 hour work = [(A + B + C)'s 1 hour work - (A + B)'s 1 hour work]   = (1/6 - 2/21) = 1/14   C alone can fill the tank in 14 hours.   Answer:14 hours
<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?