Multiple choice

Directions: Select the correct alternative from the given choices. A team of N persons can complete a certain job in 15 days. If there were six more persons in the team, it would take three days less to complete the job. Find N.

  1. 24

  2. 30

  3. 18

  4. 16
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A Correct answer
Explanation

Let the number of persons be N and days be 15. The total work is 15N. If there are N+6 persons, the time taken is 12 days, so the work is 12(N+6). Setting 15N = 12N + 72, we get 3N = 72, so N = 24.

AI explanation

The total work is calculated as the number of workers multiplied by the time taken, giving 15N person-days. If six more persons are added, the team size becomes N + 6 and the time becomes 12 days, so the work is also (N + 6) * 12. Equating the two expressions gives 15N = 12N + 72. Solving this equation yields 3N = 72, so N is 24.

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