Given,
A and B can do a piece of work in = 18 days
Work done by A and B in 1 day \(=\frac{1}{18}\)
B and C can do a piece of work in = 24 days
Work done by C and B in 1 day \(=\frac{1}{24}\)
A and c can do a piece of work in = 36 days
Work done by A and C in 1 day \(=\frac{1}{26}\)
Now adding, we get,
2(A+B+C) ’s 1 day work \(=\frac{1}{18}+\frac{1}{24}+\frac{1}{36}=\frac{4+3+2}{72}=\frac{9}{72}=\frac{1}{8}\)
A+B+C one day work \(=\frac{1}{8\times2}=\frac{1}{16}\)
∴ A, B and C can finish the work in \(=\frac{1}{\frac{1}{16}}\) =16 days