- (B) The total change in temperature of the roast 20 min after it is put in the refrigerator is
Since its temperature was 160°F when placed in the refrigerator, then 20 min later it is (160
− 89.7)°F or about 70°F. Note that the temperature of the refrigerator (45°F) is not used in
answering the question because it is already “built into” the cooling rate.