It will take 3.7 hours.
If one person can prepare one bag in 2 minutes, then 9 people (Jess + her 8 friends) can prepare 9 bags in 2 minutes. 1000/9 = 111.11; it will take 111.11 2-minute periods of time to prepare 1000 bags. 111.11(2) = 222.22 minutes total. 222.22/60 = 3.7 hours.