If A and B together can complete a piece of work in 20 days, B and C in 10 days and C and A in 12 days, then A, B and C together can complete the same work in :

[A]

[B]

[C]

[D]

(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

∴ Hence, the work will be completed in .

Hence option [C] is correct answer.