Three pipes A, B, and C fill a tank in five hours. The pipe C is twice as fast as the pipe B, and the pipe B is twice as fast as the pipe A. How long will it take pipe A to fill the tank by itself?
A. 20hours
B. 25hours
C. 35hours
D. Cannot be determined
Answer:C
Three pipes A, B, and C fill a tank in five hours. The pipe C is twice as fast as the pipe B, and the pipe B is twice as fast as the pipe A. How long will it take pipe A to fill the tank by itself?
A. 20hours B. 25hours C. 35hours D. Cannot be determined
Explanation: Assume that filling the tank using pipe A alone takes x hours.Then pipelines B and C will take x/2 and x/4 hours to fill the tank, respectively.1/x + 2/x + 4/x = 1/5,7/x = 1/5,35 hours = x.