# QA – Placement Quizzes | Pipes and Cisterns | Question 12

Two taps A and B can fill a tank in 10 hours and 15 hours respectively. If both the taps are opened together, the tank will be full in ?**(A)** 5 hr**(B)** 6 hr**(C)** 4 hr**(D)** 3 hr**Answer:** **(B)****Explanation:** If A can do a piece of work in x hours and B can do a piece of work in y hours.

Then A and B together will do the work in = 1/x+1/y

Time taken by A = 10 hours

Time taken by B = 15 hours

Time taken by A and B = (15×10 / 15+10) = 6 hours.

Quiz of this Question

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