UnofficialAP Calculus ABUnit 86 points

AP Calculus AB FRQ: Water in a Tank

A 6-point free-response question in 3 parts. Write your answer, then score it with the rubric; the model answer appears when you are ready.

Question

Water flows into a tank at a rate of

R(t) = 20 + 4t

liters per minute and drains at a constant rate of 12 liters per minute, for

0 \le t \le 10

minutes. At

t = 0

the tank holds 50 liters.(a) Is the amount of water in the tank increasing or decreasing at

t = 5

? Give a reason.(b) How many liters of water are in the tank at

t = 10

?(c) Find the average rate at which water flows into the tank over

0 \le t \le 10

Your answer

Label each part (a), (b), (c)... and show the work that justifies it. Saved in this browser as you type.