Two pipes A and B can fill a tank in 6 hours and 8 hours respectively. If both the pipes are opened together, then after how many hours should B be closed so that the tank is full in 4 hours
1). $\frac{2}{3}$ hrs
2). 1 hrs
3). 2 hrs
4). $2\frac{8}{3}$ hrs
Pipe A can fill a cistern in 6 hours and pipe B can fill it in 8 hours. Both the pipes are opened simultaneously, but after two hours, pipe A is closed. How many hours will B take to fill the remaining part of the cistern
1). 2 hrs
2). $3\frac{1}{3}$ hrs
3). $2\frac{2}{3}$ hrs
4). 4 hrs
A cistern is normally filled in 8 hours but takes another 2 hours longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in :
1). 16 hours
2). 20 hours
3). 25 hours
4). 40 hours
Two pipes, P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes. P is turned off. in how many more minutes will Q fill the cistern
1). 7 minutes
2). $7\frac{1}{2}$ minutes
3). 8 minutes
4). $8\frac{1}{4}$ minutes
A tap can fill a cistern in 40 minutes and a second tap can empty the filled cistern in 60 minutes. By mistake without closing the second tap. the first tap was opened. in how many minutes will the empty cistern be filled
1). 72
2). 84
3). 108
4). 120