A) 15 days
B) 20 days
C) 25 days
D) 30 days
Correct Answer: D
Solution :
Time taken to do by\[2\,\,(A+B+C)=\frac{xyz}{xy+yz+zx}\] Here\[x=12,\]\[y=15\]and\[z=20\] \[=\frac{12\times 15\times 20}{12\times 15+15\times 20+20\times 12}\]5 days Time taken to do work by (A+B+C)\[=2\times 5=10\]days \[\therefore \]Time taken to do work by A done\[=\frac{xy}{x-y}\] [Here x = time taken by (B + C) = 15 days and y = time taken by (A+ B+ C) = 10 days] \[=\frac{10\times 15}{15-10}=30\]daysYou need to login to perform this action.
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