(31) Pipe A can fill a tank in 4 hours, and Pipe B can fill the same tank in 6 hours. Pipe C can empty the tank in 8 hours. If all three pipes are opened simultaneously when the tank is empty, how long will it take to fill the tank completely?
- (a) 2 hours
- (b) 8 hours
- (c) 12 hours
- (d) 24 hours
(32) Pipe A can fill a cistern in 10 hours, and Pipe B can fill the same cistern in 15 hours. Pipe C can empty the cistern in 20 hours. If all three pipes are opened simultaneously when the cistern is empty, how long will it take to fill the cistern completely?
- (a) 7.5 hours
- (b) 8 hours
- (c) 9 hours
- (d) 12 hours
(33) Pipe A can fill a tank in 3 hours, and Pipe B can fill the same tank in 5 hours. Pipe C can empty the tank in 6 hours. If all three pipes are opened simultaneously when the tank is empty, how long will it take to fill the tank completely?
- (a) 2 hours
- (b) 6 hours
- (c) 8 hours
- (d) 10 hours
(34) Pipe A can fill a cistern in 12 hours, and Pipe B can fill the same cistern in 18 hours. Pipe C can empty the cistern in 9 hours. If all three pipes are opened simultaneously when the cistern is empty, how long will it take to fill the cistern completely?
- (a) 5 hours
- (b) 6 hours
- (c) 9 hours
- (d) 10 hours
(35) Pipe A can fill a tank in 4 hours, and Pipe B can fill the same tank in 6 hours. Pipe C can empty the tank in 8 hours. If all three pipes are opened simultaneously when the tank is empty, how long will it take to fill the tank completely?
- (a) 2 hours
- (b) 8 hours
- (c) 12 hours
- (d) 24 hours
