An cherry pie is taken out of the oven with an internal temperature of 338°F. It is placed on a rack in a room with a temperature of 78°F. After 18 minutes, the temperature of the pie is 225°F. What will be the temperature of the pie 20 minutes after coming out of the oven? Round to one decimal place.
A) 216.0°F
B) 215.1°F
C) 567.9°F
D) 343.6°F

Question

Quizplus · Accepted Answer

The temperature of the pie is decreasing exponentially. The rate of decrease is proportional to the difference between the temperature of the pie and the temperature of the room. After 18 minutes, the temperature of the pie is 225°F. This means that the temperature of the pie has decreased by 338°F - 225°F = 113°F. The rate of decrease is therefore 113°F / 18 minutes = 6.33°F per minute. After 20 minutes, the temperature of the pie will have decreased by 6.33°F per minute * 20 minutes = 126.6°F. Therefore, the temperature of the pie will be 225°F - 126.6°F = 216.0°F.

An Cherry Pie Is Taken Out of the Oven with an Internal