SOLUTION: A cup of coffee at 85°C is placed in a freezer at 0°C.The temperature of the coffee decreases exponentially, so that after 5 minutes it is 30°C. (a)What is its temperature afte

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: A cup of coffee at 85°C is placed in a freezer at 0°C.The temperature of the coffee decreases exponentially, so that after 5 minutes it is 30°C. (a)What is its temperature afte      Log On


   



Question 1163599: A cup of coffee at 85°C is placed in a freezer at 0°C.The temperature of the coffee decreases exponentially, so that after 5 minutes it is 30°C.
(a)What is its temperature after 3 minutes?
(b)Find by trial how long it will take for the temperature to drop ton5°C.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!




Where is the temperature in degrees C as a function of time, , in minutes, is the initial temperature at time , and is the decay constant.

The initial condition is



The 5 minute condition is:











Once you have done the indicated arithmetic to calculate a sufficiently precise approximation of to suit your particular application, you can use that value in the basic function to calculate temperature at a given time or solve for time given a temperature.


John

My calculator said it, I believe it, that settles it