A) 20 minutes
B) 10 minutes
C) 15 minutes
D) 5 minutes
Correct Answer: A
Solution :
Part of cistern filled by inlets A and B together in one minute \[=\frac{1}{12}+\frac{1}{15}=\frac{5+4}{60}=\frac{9}{60}\] and part of cistern emptied by outlet C in 1 minute \[=\frac{1}{10}\] So, part of the cistern filled in one minute when all three pipes are opened simultaneously, \[=\frac{9}{60}-\frac{1}{10}=\frac{9-6}{60}=\frac{3}{60}=\frac{1}{20}\] So, time required to fill the cistern = 20 mins.You need to login to perform this action.
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