Which of the following statements is correct about man-hours related to 5 men completing a job?

The concept of man-hours refers to the total amount of work done by a person over a specific period of time. In this scenario, to understand how many hours 5 men take to complete a job, we need to look at the total man-hours involved.

If 5 men work together to complete a job, and it takes them 12 hours, the total man-hours expended is calculated by multiplying the number of workers (5) by the number of hours they work (12). This results in 5 men × 12 hours = 60 man-hours. This means that the job requires a total of 60 man-hours to complete.

When comparing the first statement with the others, we see that each option implies a different combination of men and hours. Only the first option maintains the necessary total of 60 man-hours, making it the correct choice. The other statements would either reduce this total or misrepresent the time taken to complete the job with the same number of workers.