Multiple choice

P alone can complete a work in 12 days while P and Q together can complete the same work in 8 days. Find the number of days that Q will take to complete the work alone?

  1. 10

  2. 24

  3. 20

  4. 9
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

P's rate = 1/12. (P+Q)'s rate = 1/8. Q's rate = 1/8 - 1/12 = 3/24 - 2/24 = 1/24. Q takes 24 days.

AI explanation

Using the combined work formula, Q's 1 day work equals the combined 1 day work minus P's 1 day work, giving 1/8 minus 1/12. This simplifies to 1/24, so Q alone takes the reciprocal of 1/24, which is 24 days.

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