A tank can be filled by two pipes in 20 minutes and 30 minutes respectively. When the tank was empty, the two pipes were opened. After some time, the first pipe was stopped and the tank was filled in 18 minutes. After how much time of the start was the first pipe stopped
1). 5 minutes
2). 8 minutes
3). 10 minutes
4). 12 minutes
A tank is fitted with two taps.The first tap can fill the tank completely in 45 minutes and the second tap can empty the full tank in one hour. If both the taps are opened alternately for one minute, then in how many hours the empty tank will be filled com- pletely
1). 2 hours 55 minutes
2). 3 hours 40 minutes
3). 4 hours 48 minutes
4). 5 hours 53 minutes
Two pipes A and B can fill a cistern in $37\frac{1}{2}$ minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled just in half an hour, If the pipe B is turned off after :
1). 15 minutes
2). 10 minutes
3). 5 minutes
4). 9 minutes
A tap can fill a tank in 6 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely
1). 4 hours
2). 4 hours 15 minutes
3). 3 hours 15 minutes
4). 3 hours 45 minutes
A pipe can fill a tank with water in 3 hours. Due to leakage in bottom,it takes $3\frac{1}{2}$ hours to fill it.in what time the leak will empty the fully filled tank
1). 12 hours
2). 21 hours
3). $6\frac{1}{2}$ hours
4). $10\frac{1}{2}$ hours