Practice | Hashtable

Home > Practice > Arithmetic Aptitude > Pipes and Cisterns > Miscellaneous

1. A water tap fills a tub in 'p' hours and a sink at the bottom empties it in 'q' hours. If p < q and both tap and sink are opened the tank is filled in 'r' hours, then the relation between p, q, r :

A. $\frac{1}{r} = \frac{1}{p} + \frac{1}{q}$

B. $\frac{1}{r} = \frac{1}{p} - \frac{1}{q}$

C. $r = p + q$

D. $r = p - q$

Solution:

Net efficiency = q - p (∵ q > p)
Time required

\begin{aligned} r = \frac{p q}{q - p} \\ o r \frac{1}{r} = \frac{1}{p} - \frac{1}{q} \end{aligned}

You must login to add comments. Login now.