Question

ou place a cup of 210oF coffee on a table in a room that is 68oF, and 10 minutes later, it is 200oF. Approximately how long will it be before the coffee is 180oF? Use Newton's law of cooling
http://i.imgur.com/KCuZlK4.png
1 hour

35 minutes

15 minutes

45 minutes

Answer 1

Maybe 15mins...

Answer 2

I have closer to 35 minutes but need to run the formula through again.

(My working answer is 32.5 minutes.)

I used this to find the cooling constant:

200 = 68 + (210 - 68)*e^(-10k)

and then this equation for the time of cooling to 180 ° F

180 = 68 + (210 - 68)*e^(-.0073025t)

Answer 3

i got the same thing