Four pipes A, B, C and D can fill a tank in 6, 8 , 10 and 12 hours resp. If pipe A was opened at 7: 00 a.m. pipe B at 8: 00, pipe C at 9: 00 a.m. and pipe D at 10: 00 a.m. , at what approximate time at what time the tank was filled?
(A) 10: 19 a.m.
(B) 10: 25 a.m.
(C) 10: 40 a.m.
(D) 10: 50 a.m.
Three pipes X, Y , Z are fitted to an empty tank, they are opened simultaneously . The time take by X to fill the tank is 6 times the time taken by all the three pipes to fill the tank . The time taken by Y to fill the tank is 40 hours less than seven times the time taken by all the three pipes to fill the tank. The time taken by Z to fill the tank is 10 hours more than the time taken by all the three pipes to fill the tank. If the time taken to fill the tank is an integer (in hours). Then find the most efficient pipe.
(A) X
(B) Y
(C) Z
(D) All are equally efficient
