Exams › SSC CGL (Prelims) › General

X and Y complete a task in 14 days, and Y and Z complete it in 18 days. If X works for 6 days, Y for 8 days, and Z for 12 days to complete the task, how many days will Z alone take approximately?

1. 20 days
2. 22 days
3. 28 days
4. 30 days

Correct answer: 22 days

Solution

Let the daily work rates be X, Y, Z. Then X+Y = 1/14 and Y+Z = 1/18. The total work done is 6X + 8Y + 12Z = 1. Solving these equations gives Z ≈ 1/22 of the work per day, so Z alone takes about 22 days.

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