A vessel has three pipes connected to it, two to supply liquid and one to draw liquid. The first alone can… · ABC26GN3402
Subject: General Aptitude · Chapter: Pipes and Cisterns · Exam: M.B.A. 2007
A vessel has three pipes connected to it, two to supply liquid and one to draw liquid. The first alone can fill the vessel in $4 \frac{1}{2}$ hours, the second in 3 hours and the third can empty it in $1 \frac{1}{2}$ hours. If all the pipes are opened simultaneously when the vessel is half full, how soon will it be emptied?
(a)$4 \frac{1}{2}$ hours
(b)$5 \frac{1}{2}$ hours
(c)$6 \frac{1}{2}$ hours
(d)None of these
Answer
Answer (as printed): A
Explanation
Net part emptied in 1 hour $= \frac{2}{3} - \left(\frac{2}{9}+\frac{1}{3}\right) = \frac{1}{9}$. $\therefore \frac{1}{9} : \frac{1}{2} :: 1 : x$ or $x = \frac{1}{2} \times 9 = 4\frac{1}{2}$ hours. So, the tank will be emptied in $4\frac{1}{2}$ hours.
Explanation as extracted from the printed page; notation may be imperfect.