Three pipes A, B, C are attached to a cistern. Pipe A and B can fill the cistern in 20 and 30 hours respectively and the pipe C can empty it in 60 hrs. Pipe A and C are opened for the 1st Hour and the pipe B and C are opened for the next hour and this process continues till the cistern get filled. In how much time the tank will get filled ?

Options

A. 30 hours
B. 40 hours
C. 45 hours
D. 20 hours

Answer

B