Multiple choice

A and B together can do a work in 9 days, B and C can do it in 12 days and A and C can do it in 18 days. In how many days can A, B and C together do it?

  1. 8

  2. 6

  3. 5

  4. 4

  5. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

2(A+B+C) = 1/9 + 1/12 + 1/18 = (4+3+2)/36 = 9/36 = 1/4. A+B+C = 1/8. So they take 8 days.

AI explanation

Using the work and time formula, add the combined daily rates: 1/9 plus 1/12 plus 1/18 equals 9 divided by 36, which is 1/4. This sum equals twice the combined daily work of A, B, and C. Therefore, their combined daily work is 1/8, meaning they finish the job in 8 days.

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