Multiple choice

If X and Y can complete a piece of work in 15 days, and X alone can do the same work in 30 days, find how many days will Y alone take to complete the same work?

  1. 60 days

  2. 45 days

  3. 30 days

  4. 15 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Work rate of (X+Y) = 1/15. Work rate of X = 1/30. Work rate of Y = 1/15 - 1/30 = 1/30. Y takes 30 days.

AI explanation

Using the combined work formula, Y's one-day work is the difference of X and Y's combined one-day work and X's one-day work. This gives 1/15 minus 1/30, which equals 1/30. Therefore, Y alone takes 30 days to complete the work.

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