Pipes A and B can fill a tank in 10 hours and 40 hours, respectively. C is an outlet pipe attached to the tank. If all the three pipes are opened simultaneously, it takes 80 minutes more time than what A and B together take to fill the tank A and B are kept open for 7 hours and then closed and C was opened. C will now empty the tank in:

Options

A. 49 hours
B. 38.5 hours
C. 42 hours
D. 45.5 hours

Answer

A