A) 10
B) 20
C) 30
D) 60
Correct Answer: C
Solution :
(P + Q)'s1 day's work\[=\frac{1}{12}\] ...(i) (Q+R)'s1 day's work\[=\frac{1}{15}\] ...(ii) (R + P)'s 1 day's work\[=\frac{1}{20}\] ...(iii) Adding all three equations, we get 2 (P+Q+R)'s 1day's work \[=\frac{1}{12}+\frac{1}{15}+\frac{1}{20}=\frac{5+4+3}{60}=\frac{12}{60}=\frac{1}{5}\] \[\because \](P + Q + R)'s 1 day's work \[\frac{1}{10}\] ...(iv) \[\therefore \]P's 1 day's work = Eq. (iv) - Eq.(ii) \[=\frac{1}{10}-\frac{1}{15}=\frac{3-2}{30}=\frac{1}{30}\] \[\therefore \]P alone will complete the work in 30 days.You need to login to perform this action.
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