00:01
So pizza is removed from an oven at 10 p .m.
00:05
And the temperature of the oven is 400 degrees.
00:09
So that is my initial temperature.
00:14
The pizza is put in a room that's a constant 73 degrees.
00:17
So room temperature is 73 degrees.
00:22
And then we're told after five minutes, the pizza is 300.
00:32
So we're going to use that information to get the cooling room.
00:36
K.
00:38
So 73 plus 400 minus 73, e to the k times 5, and that's going to equal 300.
00:50
So let's subtract 73 from both sides.
00:55
So i have 227 equals 400 minus 73 is 327, e to the 5k.
01:08
Divide both sides by 327.
01:14
You are going to get 0 .6942 equal to e to the 5k.
01:21
Take the ln of both sides.
01:28
Bring your exponent down.
01:30
Ln of e is just one.
01:33
Divide by 5, and we'll get a value of k.
01:40
That is negative 0 .0730.
01:45
We want to determine what time the temperature is 135.
01:56
Okay, so set your function equal to 135...