Hi angandbri and welcome to the forum,

This sounds like a high school math word problem. Lets see if this makes sense
8 People stuff 345 items in 7.5 hours (given)
Divide all numbers above by 8 so
1 persons stuff 43.125 items in .9375 hours
Now divide all by 43.124 to get 1 item stuffed.
.9375 / 43.125 = .021739 hours.
Multiply the hours by 60 to convert it to minutes and get 1.304348 minutes to stuff an item.

See if that makes sense to you.