2024 AP Calculus AB FRQ Problem 1

The problems are the property of College Board. This video is submitted for educational purposes under general use.
Prompt - 0:00
Part A - 0:18
Part B - 1:29
Part C - 3:54
Part D - 6:28
MY MISTAKE - 100 is positive, not negative - 8:10
WRONG ANSWER - Because C" is positive, the rate is changing at an INCREASING rate - 9:36

[@Alex.LopezC]

For part A, 69 - 85 = -16, not -14, so instead of your answer being -7/2, it should be -4 degrees.

[@PrecisionTutoring]

Great catch! I should have used my calculator to double check that.

[@rospore5586]

For part d. Isn't C''(t) > 0? since the term (100-t) in the numerator should always be positive on the interval 12 < t < 20, but you wrote it as being negative.

[@PrecisionTutoring]

Great catch! Thanks.

[@BareMinimum2]

For part B, do we have to solve for average value because it only asks what's the meaning?

[@PrecisionTutoring]

You make a valid point that they don't ask for the numerical value of the average value. Since they only ask for the MEANING, you might get away with not including its value. I chose to include it in case they expected you to include the value in the explanation of the meaning.
We will see what College Board says after they publish their Scoring Guidelines.