It takes 6 technicians a total of 10 hours to build a new server from Direct Computer, with each technician working at the same rate. If six technicians start to build the server at 11:00 AM, and one technician per hour is added beginning at 5:00 PM, at what time will the server be built?

Explanation:

Total time taken to build the server = 60 man hours.

6 of them start at 11:00 AM and work till 5 PM.

They will complete 6×6 = 36 man hours of work.

At 5 PM they will have 24 more man hours of work to complete.

Between 5 PM and 6 PM they will complete 7 man hours.

Between 6 PM and 7 PM they will complete 8 man hours.

Between 7 PM and 8 PM they will complete 9 man hours.

So, by 8 PM 36 + 7 + 8 + 9 = 60 man hours of work will be done

or the server will be built by 8 PM.