It takes, 2, minutes to prepare one bag. If Ashley works alone, it will take her 900 bags× 2 minutes each =1800 minutes to prepare the bags.
Since there are 60 minutes in an hour, that's the same as 1800/60 which equals to 30 hours. If there are 6 people sharing Ashley's work Ashley + 5 friends the work will be finished 6 times as fast.
A team of 6 people can finish the job 30/6 which equals 5