Pipe A alone can fill a tank in 8 minutes. Pipe B alone can fill the same tank in 12 minutes. Both the pipes are opened together when the tank is empty. However, Pipe B is closed 3 minutes before the tank is full. In what time did the tank get filled?
Correct Answer: Description for Correct answer:
A Pipe A is kept open till the tank gets filled.
Let the time for which Pipe A is kept open = t minutes
Therefore, pipe B was kept open for (t - 3) minutes only.
Pipe A fills \( \Large \frac{1}{8} \)th of the tank in a minute and pipe B fills \( \Large \frac{1}{12} \)th of the tank every minute.
Together (A was open for t minutes and B for t-3 minutes) pipe A and pipe B fill ONE full tank
i.e. \( \Large \frac{t}{8}+\frac{t-3}{12}=1\ or\ \frac{3t+2t-6}{24}\ or\ 5t = 30\ or\ 5=6 minutes \)
Part of solved Pipes and Cisterns questions and answers :
>> Aptitude >> Pipes and Cisterns