Pipes and Cistern
1. Pipe A can fill a tank in 20 hours. Pipe B can fill the same tank in 30 hours. How long will both pipes take to fill the tank together?
A. 10 hours
B. 12 hours
C. 15 hours
D. 18 hours
B. 12 hours
2. A pipe can fill a tank in 10 hours, and another pipe can empty it in 15 hours. If both are opened together, how long will it take to fill the tank?
A. 15 hours
B. 20 hours
C. 25 hours
D. 30 hours
C. 25 hours
3. Two pipes A and B can fill a tank in 15 hours and 20 hours respectively. If both are opened together, how long will it take to fill the tank?
A. 8.57 hours
B. 10 hours
C. 8 hours
D. 12 hours
A. 8.57 hours
4. Pipe A can fill a tank in 12 hours. Pipe B is 50% more efficient than A. How long will B take to fill the tank?
A. 8 hours
B. 10 hours
C. 12 hours
D. 15 hours
A. 8 hours
5. Pipe A can fill a tank in 8 hours, and pipe B can empty it in 12 hours. If both are opened together, how long will it take to fill the tank?
A. 20 hours
B. 15 hours
C. 10 hours
D. 24 hours
D. 24 hours
6. A tank is filled by pipe A in 4 hours and by pipe B in 6 hours. How long will it take to fill the tank if both are opened together?
A. 2 hours 15 min
B. 2 hours 24 min
C. 3 hours
D. 3 hours 30 min
B. 2 hours 24 min
7. A tank can be filled by a pipe in 5 hours and emptied by another in 8 hours. If both are opened simultaneously, how long will it take to fill the tank?
A. 3/40
B. 5/8
C. 8/5
D. 40/3
D. 40/3
8. Pipe A can fill a tank in 16 hours and Pipe B in 12 hours. How long will it take to fill the tank if both are opened together?
A. 7/48
B. 48/7
C. 48
D. 5/48
B. 48/7
9. Two pipes can fill a tank in 20 and 30 minutes respectively. A third pipe can empty the tank in 40 minutes. How long will it take to fill the tank if all three pipes are opened together?
A. 7/120
B. 1/40
C. 40/3
D. 120/7
D. 120/7
10. A cistern can be filled by a tap in 7 hours and emptied by another tap in 14 hours. If both are opened together, how long will it take to fill the cistern?
A. 10 hours
B. 12 hours
C. 14 hours
D. 16 hours
C. 14 hours