Answer:
53.33 minutes
Explanation:
1 lb = 16 oz
600 x 16 = 9600
600 lbs = 9600 oz every 8 hours needed
15 x 3 = 45 oz every 2 minutes produced
45 / 2 = 22.5 oz every 1 minute procuded
8 x 60 = 480 minutes in 8 hours
9600 = 22.5x = 9600 / 22.5 = 426.67 minutes until complete
480 - 426.67 = 53.33 minutes of downtime