A) 10
B) 20
C) 30
D) 60
Correct Answer: C
Solution :
(P + Q)s 1 day?s work \[=\frac{1}{12}\] ?(i) (Q + R)?s 1 day?s work \[=\frac{1}{15}\] ? (ii) (R + P)?s 1 day?s work \[=\frac{1}{20}\] ? (iii) Adding all three Eqs. 2(P + Q + R)?s 1 day?s work \[=\frac{1}{12}+\frac{1}{15}+\frac{1}{20}=\frac{5+4+3}{60}=\frac{12}{60}=\frac{1}{5}\] \[\therefore \] (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 along will complete the work in 30 days.You need to login to perform this action.
You will be redirected in
3 sec