A cistern has two pipes. One can fill it with water in 8 hours and other can empty it in 5 hours. In how many… · ABC26GN3401
Subject: General Aptitude · Chapter: Pipes and Cisterns
A cistern has two pipes. One can fill it with water in 8 hours and other can empty it in 5 hours. In how many hours will the cistern be emptied if both the pipes are opened together when $\frac{3}{4}$ of the cistern is already full of water?
(a)$3 \frac{1}{3}$ hours
(b)6 hours
(c)10 hours
(d)$13 \frac{1}{3}$ hours
Answer
Answer (as printed): C
Explanation
Net part emptied in one hour = − = . 5 8 40 3 3 3 40 ∴ : : : 1 : x or x = × 1 × = 10 hrs. 40 4 4 3 So, the cistern will be emptied in 10 hrs. 2 2 1 2 5
Explanation as extracted from the printed page; notation may be imperfect.