A) 12 h
B) \[13\frac{1}{2}\,\,\text{h}\]
C) 15 h
D) 21 h
Correct Answer: A
Solution :
Part filled in 10 h \[=\frac{1}{10}\left[ \frac{1}{15}+\frac{1}{20}-\frac{1}{25} \right]=\frac{23}{30}\] Remaining part \[=\left[ 1-\frac{23}{30} \right]=\frac{7}{30}\] \[\left[ \frac{1}{15}+\frac{1}{20} \right]\]part is filled by P and Q in 1 h \[\frac{7}{30}\]part will be filled by them in \[\left[ \frac{60}{7}\times \frac{7}{30} \right]\]= 2 h \[\therefore \]Total time taken \[=(10+2)=12\,\,\text{h}\]You need to login to perform this action.
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