A tap can fill a cistern in 8 hours and another tap can empty it in 16 hours. If both the taps are open, the time (in hours) taken to fill the tank will
1). 8
2). 10
3). 16
4). 24
Two pipes can fill a tank in 15 hours and 20 hours respectively, while the third can empty it in 30 hours. If all the pipes are opened simultaneously , the empty tank will be filled in
1). 10 hours
2). 12 hours
3). 15 hours
4). $15\frac{1}{2}$ hours
Two pipes can fill a cistern in 3 hours and 4 hours respectively and a waste pipe can empty it in 2 hours. If all the three pipes are kept open , then the cistern will be filled in :
1). 5 hours
2). 8 hours
3). 10 hours
4). 12 hours
Two pipes A and B can separately fill a cistern in 60 minutes and 75 minutes respectively. There is a third pipe in the bottom of the cistern to empty it. If all the three pipes are simultaneously opened, then the cistern is full in 50 minutes. in how much time the third pipe alone can empty the cistern
1). 110 minutes
2). 100 minutes
3). 120 minutes
4). 90 minutes
A cistern can be filled with water by a pipe in 5 hours and it can be emptied by a second pipe in 4 hours. If both the pipes are opened when the cistern is full, the time in which it will be emptied is :
1). 9 hours
2). 18 hours
3). 20 hours
4). $20\frac{1}{2}$ hours