Final answer:
To calculate the total work hours for the person, we add the hours worked before lunch (2 hours and 45 minutes) to the hours worked after lunch (4 hours and 45 minutes), totaling 7.5 hours.
Step-by-step explanation:
To determine how many hours the person worked, we must subtract the times they were not working from the total time spent at work. We calculate the working hours in two segments: from their arrival to lunch and from lunch to the end of the workday.
First, from 8:30 a.m. to 11:15 a.m. is 2 hours and 45 minutes.
Then, they returned at 12:30 p.m. and worked until 5:15 p.m., which is 4 hours and 45 minutes.
We add both work periods together: 2 hours 45 minutes + 4 hours 45 minutes equals 7 hours and 30 minutes, or 7.5 hours.
Therefore, the person worked for a total of 7.5 hours.