A and B can do a job in 6 days, B and C in 9 days, and A and C in 12 d

1.	A and B can do a job in 6 days, B and C in 9 days, and A and C in 12 days. How much timewill they take to complete the job if they all work together? How long will each of them taketo do the job?
Answer» Answer: $\frac{72}{13}$ days Step-by-step explanation: Let us GIVE the JOB a value of 1. A and B require 6 days to finish the job ⇒A and B finish $\frac{1}{6}$ of the job in 1 day. A + B = $\frac{1}{6}$ Similarly we can say that, B + C = $\frac{1}{9}$ and A + C = $\frac{1}{12}$ Adding all of these, A + B + B + C + C + A = $\frac{1}{6}$ + $\frac{1}{9}$ + $\frac{1}{12}$ 2A + 2B + 2C = $\frac{6+4+3}{36}$ 2(A + B + C) = $\frac{13}{36}$ A + B + C = $\frac{13}{72}$ Therefore, they can complete the WORK in $\frac{72}{13}$ days.