Average rate of change over an interval

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. Read this first

   Use the table

   input d: days	output snacks
   1	2
   3	5
   5	11
   7	20
   9	41

2. 1.

   Tala sells snacks from a cart. The table shows the total sold. What is the average rate of change from 3 to 9?

   6
3. 2.

   Zee counts riders on a bus. The table shows riders on board. What is the average rate of change from 5 to 20?

   4
4. 3.

   Ari's tree grows, a little faster each month. The table shows its height in cm. What is the average rate of change from 3 to 12?

   7
5. 4.

   Bo's game score is f(x) = x² + 2x after x rounds. What is the average rate of change from 1 to 4?

   7
6. 5.

   Esme's bakery sells f(x) = 2x² + x cookies on day x. What is the average rate of change from 1 to 3?

   9
7. 6.

   Jun's bike ride covers f(x) = 4x + 3 km in x hours. What is the average rate of change from 2 to 6?

   4
8. 7.

   Kira's robot builds f(x) = x² + 5 blocks in x minutes. What is the average rate of change from 2 to 6?

   8
9. 8.

   Noah's tent pole is pushed up. The graph shows its height in cm. What is the average rate of change from x = 4 to x = 8?

   4
10. 9.

    Pia's plant has an average rate of change in height of 3 cm per week from week 2 to week 6. Which sentence is right?

    • The plant is 3 cm tall at week 6
    • The plant grew 3 cm in total from week 2 to week 6, over the whole stretch
    • On average, the plant grew 3 cm each week from week 2 to week 6
11. 10.

    Tala's savings have an average rate of change of $5 per week from week 0 to week 8. Which sentence is right?

    • The savings grew $5 in total from week 0 to week 8
    • The savings are $5 at week 8
    • On average, the savings grew $5 each week from week 0 to week 8