Subject: General Aptitude · Chapter: Pipes and Cisterns · Exam: · Marks: · Difficulty:
A tap can fill a tank in 6 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely?
(a)3 hrs 15 min
(b)3 hrs 45 min
(c)4 hrs
(d)4 hrs 15 min
Answer
Answer (as printed): B
Explanation
Time taken by one tap to fill half the tank = 3 hrs. Part filled by the four taps in one hour $= 4 \times \frac{1}{6} = \frac{2}{3}$. Remaining part $= \frac{1}{2}$. $\therefore \frac{2}{3} : \frac{1}{2} :: 1 : x$ or $x = \frac{1}{2} \times 1 \times \frac{3}{2} = \frac{3}{4}$ hrs i.e. 45 min. So, total time taken = 3 hrs 45 min.
Explanation as extracted from the printed page; notation may be imperfect.