(16) Pipe A can fill a tank in 8 hours, and Pipe B can fill the same tank in 12 hours. If both pipes are opened simultaneously, how long will it take to fill the tank if initially, it is already filled to 25% of its capacity?
- (a) 2 hours
- (b) 3 hours
- (c) 4 hours
- (d) 5 hours
(17) Pipe A can fill a tank in 4 hours, and Pipe B can empty the same tank in 6 hours. If both pipes are opened simultaneously, how long will it take to empty the tank completely?
- (a) 2 hours
- (b) 3 hours
- (c) 4 hours
- (d) 6 hours
(18) Pipe A can fill a cistern in 8 hours, and Pipe B can fill the same cistern in 12 hours. Pipe C can empty the cistern in 6 hours. If all three pipes are opened simultaneously when the cistern is empty, how long will it take to fill the cistern completely?
- (a) 4 hours
- (b) 6 hours
- (c) 8 hours
- (d) 10 hours
(19) Pipe A can fill a tank in 5 hours, and Pipe B can fill the same tank in 10 hours. Pipe C can empty the tank in 15 hours. If all three pipes are opened simultaneously when the tank is empty, how long will it take to fill the tank completely?
- (a) 4 hours
- (b) 5 hours
- (c) 6 hours
- (d) 7 hours
(20) Pipe A can fill a cistern in 9 hours, and Pipe B can fill the same cistern in 12 hours. Pipe C can empty the cistern in 18 hours. If all three pipes are opened simultaneously when the cistern is empty, how long will it take to fill the cistern completely?
- (a) 6 hours
- (b) 8 hours
- (c) 10 hours
- (d) 12 hours
