A swimming pool has 3 drain pipes. The first two pipes A and B, operating simultaneously, can empty the pool in half the time that C, the 3rd pipe, alone takes to empty it. Pipe A, working alone, takes half the time taken by pipe B. Together they take 6 hours 40 minutes to empty the pool. Time taken by pipe A to empty the pool. (in hours) is
1). 15
2). 10
3). 30
4). 7
Two pipes A and B can fill a water tank in 20 and 24 minutes respectively and a third pipe C can empty at the rate of 3 gallons per minute. If A, B and C are opened together to fill the tank in 15 minutes, the capacity (in gallons) of the tank is:
1). 180
2). 150
3). 120
4). 60
A pipe of diameter d can drain a certain water tank in 40 minutes. The time taken by a pipe of diameter 2d for doing the same job in :
1). 5 minutes
2). 10 minutes
3). 20 minutes
4). 80 minutes
A Boy and girl together fill a cistern with water. The boy pours 4 litres of water every 3 minutes and the girl pours 3 litres every 4 minutes. How much time will it take to fill 100 litres of water in the cistern
1). 36 minutes
2). 42 minutes
3). 48 minutes
4). 44 minutes
Two pipes can fill a tank with water in 15 and 12 hours respectively and a third pipe can empty it in 4 hours. If the pipes be opened in order at 8, 9 and 11 a. m. respectively, the tank will be emptied at
1). 11:40 a.m.
2). 12:40 p.m
3). 1:40 p.m.
4). 2:40 p.m.