A) 6 days
B) 5 days
C) 4 days
D) 7 days
Correct Answer: C
Solution :
\[\left( A+B+C \right)'\]s two day?s work \[=2\times \left( \frac{1}{12}+\frac{1}{15}+\frac{1}{20} \right)\] \[=2\times \left( \frac{5+4+3}{60} \right)=\frac{24}{60}=\frac{2}{5}\] \[\therefore \]After two days, remaining work\[=1-\frac{24}{60}=\frac{2}{5}\] \[\left( A+B \right)'\]s 1 day work \[=\frac{1}{12}+\frac{1}{15}=\frac{5+4}{60}=\frac{9}{60}=\frac{3}{20}\]part \[\because \frac{3}{20}\]part complete in = 1 day \[\therefore \frac{3}{5}\]part complete in \[=1\times \frac{20}{3}\times \frac{3}{5}=4\]daysYou need to login to perform this action.
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