Two pipes A and B can fill a tank in 18 minutes and 24 minutes respectively. If both the pipes are opened simultaneously, then after how much time should pipe B be closed so that the tank is full in 12 minutes?
Answer & explanation
Correct answer: option 3
Let B be opened for X min,
According to the question,
\(\frac{12}{18}\) + \(\frac{X}{24}\) = 1,
\(\frac{X}{24}\) = 1 - \(\frac{2}{3}\) = \(\frac{1}{3}\)
X = 8 min.
Therefore, Pipe B is opened for 8 mins.