Aunt Malou keeps her house at 20 degrees Celsius. She just made a fresh cup of hot tea. Tea is made with boiling water, and the temperature of boiling water is 100 degrees Celsius. Five minutes after she pours her tea, her 'mad scientist' nephew arrives and sticks a thermometer in the cup of tea. He announces that the tea is now only 70 degrees Celsius. Apparently Aunt Malou got busy reading her book and forgot about her tea. Now, she won't drink her tea since it is no longer piping hot. First, list ALL the relevant data.

Second, create an equation, using the form y=abx+k
y
=
a
b
x
+
k
to model the situation.

Then, use your equation to identify the temperature of the tea after 30 minutes (from when Aunt Malou made it).

Last, use your equation to determine when the tea will be 28 degrees Celsius.