Two pipes A and B can independently fill a tank completely in 20 and 30 minutes respectively. If both the pipes are opened simultaneously, how much time will they take to fill the tank completely?
12 mins
To solve such type of questions, we will first know that how much tank is filled by both the pipes in 1 minute and after getting that result, we will simply add them as shown: Now the time taken by pipe A to completely fill the tank is 20 minutes, while time taken by pipe B to completely fill the tank is 30 minutes. Initially we will find quantity of water filled by both pipes in a tank in 1 minute. Quantity of water filled by pipe A in a tank 1 min = 1/20 Quantity of water filled by pipe B in a tank in 1 min = 1/30 So total Quantity of water filled by both pipes A and B ie (A+B) in 1 min = 1/20 + 1/30 = 1/12 So we see that both pipes A and B can fill the tank in 12 minutes, which is option B.
Important Questions from Pipe and Cistern
The compound interest on Rs. 64,000 for 3 years, compounded annually at 7.5% p.a. is
A water tank can be emptied in 40 minutes by a pipe of d 'diameter, so how long will it take for a 2d diameter pipe to be emptied?
Two pipes X and Y can fill an empty tank in 16 hours and 20 hours respectively. Pipe Z alone can empty the completely filled tank in 25 hours. Firstly both pipes X and Y are opened and after 6 hours pipe Z is also opened. What will be the total time (in hours) taken to completely fill the tank?
Pipe J can fill a tank in 48 hours and pipe K can fill the same tank in 72 hours. If both the pipes are opened alternately for one hour each and pipe K is opened for the first hour, then in how much time the tank will be full?
Two pipes A and B can fill a cistern in 9 minutes and 6 minutes respectively. Both the pipes are turned on simultaneously. When should the second pipe be closed, if the cistern is to be filled in 4 minutes?
