A and B together can complete a piece of work in 18 days, B and C in 24 days and A and C in 36 days. In how many days, will all of them together complete the work?

[A]10 days

[B]12 days

[C]15 days

[D]16 days

**16 days**

(A + B)’s 1 day’s work

(B + C)’s 1 day’s work

(C + A)’s 1 day’s work

On adding,

2(A + B + C)’s 1 day’s work

∴ (A + B + C)’s 1 day’s work

∴ A, B and C together will complete the work in 16 days.

Hence option [D] is correct answer.