A) 15 days
B) 20 days
C) 25 days
D) 30 days
Correct Answer: C
Solution :
(c): Let A, B, C alone do work in x, y & 50 days. B + C can do it in \[\frac{1}{\frac{1}{y}+\frac{1}{50}}\] \[\therefore x=\frac{1}{\frac{1}{y}+\frac{1}{50}}\] \[\therefore \frac{1}{x}=\frac{1}{y}+\frac{1}{50}\] ???.I A+ B together can do in \[\frac{1}{\frac{1}{x}+\frac{1}{y}}=10\] days . \[\frac{1}{x}+\frac{1}{y}=\frac{1}{10}\] ??..II Adding I & II, \[\Rightarrow \frac{2}{x}=\frac{1}{50}+\frac{1}{10}=\frac{6}{50}\] \[\Rightarrow x=\frac{100}{6}=50/3\] \[\Rightarrow \frac{3}{50}+\frac{1}{y}=\frac{1}{10}\]. \[\Rightarrow \frac{1}{y}=\frac{2}{50}\Rightarrow y=25\]days.You need to login to perform this action.
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