Explanation:

- Let's define work rates:

- A and B together complete the work in 18 days.

- B and C together complete the work in 24 days.

- A and C together complete the work in 36 days.

- Calculate combined work rate of A, B, and C:

- A + B = 1/18 of work per day

- B + C = 1/24 of work per day

- A + C = 1/36 of work per day

- Add all equations:

- (A + B) + (B + C) + (A + C) = 1/18 + 1/24 + 1/36

- Simplify to find the rate of 2(A + B + C):

- 2(A + B + C) = (4 + 3 + 2)/72 = 9/72 = 1/8

- Therefore, A, B, and C together can complete the work in half the time:

- A + B + C = 1/16 of work per day

- So, A, B, and C can complete the work together in 16 days.

- Option 2 - 16 days is the correct answer.

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