Question

Two tubes can fill a reservoir in 7 hrs and 8 hrs each. The tubes are opened together and due to a leakage, it takes 16 mins more to fill up the reservoir. When the reservoir fills up, how long will the leakage take to empty it?

• A. 50 hrs
• B. 56 hrs
• C. 80 hrs
• D. 90 hrs

Answer 1

The correct option is B

56 hrs

Work done by the two tubes in 1 hr = ($\frac{1}{7}$ + $\frac{1}{8}$) = $\frac{15}{56}$

Total time taken due to leakage = 3 hrs 44 mins + 16 mins = 4 hrs

Work done by the leakage in 1 hr = $\frac{15}{56}$ - $\frac{1}{4}$= $\frac{1}{56}$

So the leakage will empty the reservoir in 56 hrs.