Not too sure where to post this but its a basic math problem:

Shift Hours: 8:00-15:30

Number of man hours to complete a car: 12hr

Total Workers per day: 117

Target cars per day: 80

If the target for cars produced per day where to increase to 100 without increasing the number of staff, what time roughly would be daily shift end (assume normal start 8:00) to meet this target?

The ans is either 16:45, 17:30, 18:15, 19:00 or 19:45

Many Thanks for you help!