Multiple choice

A crew of workers is tasked with repairing a road. If all work together, they can complete the job in 12 days. If half of the crew works for the first 8 days, and the remaining half joins them afterward, how many more days will it take to complete the job?

  1. 5 days

  2. 6 days

  3. 7 days

  4. 8 days

  5. 9 days
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the total work be 12 units (1 unit/day). Half crew (0.5 units/day) works for 8 days, completing 4 units. Remaining work is 8 units. Now the full crew (1 unit/day) works, taking 8/1 = 8 days.

AI explanation

Using the standard work equation, let the total work be 1 whole unit and the full crew's work rate be 1/12 of the job per day. If half the crew works for 8 days, their rate is 1/24 of the job per day, meaning they complete 8/24 or 1/3 of the job. The remaining 2/3 of the job is then completed by the full crew, which takes (2/3) divided by (1/12) days. This calculation yields exactly 8 additional days to complete the job.

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