A) 10 h
B) 16 h
C) 18 h
D) 20 h
Correct Answer: D
Solution :
The part of cistern which can be filled in \[1\,\,\text{h}=\frac{1}{5}\] When the part of cistern which can be emptied in\[1\,\,\text{h}=\frac{1}{4}\] While both the taps are opened, cistern part can be emptied in\[1\,\,\text{h}=\frac{1}{4}-\frac{1}{5}=\frac{5-4}{20}=\frac{1}{20}\] Therefore, the required time to empty the cistern is 20 h.You need to login to perform this action.
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