A huge pack of meat with initial temperature of 24°C was placed into a freezer that usually maintained to its constant temperature of -20°C After 3 hours, the temperature of the meat was change to...

Extracted text: A huge pack of meat with initial temperature of 24°C was placed into a freezer that usually maintained to its constant temperature of -20°C After 3 hours, the temperature of the meat was change to 6°C. According to the Department of Food Science and Nutrition, the meat can be transported once it reach -18°C. How long (in hours) we have to wait before the meat is ready to be transported? (unit not needed)