Average rate of change over an interval

Answer Key - Grade 9 Math Worksheet - Building Confidence

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

1. Read this first

   Use the table

   input w: weeks	output cm
   1	5
   2	6
   3	11
   4	20

2. 1.

   Ren's plant is measured each week (height in cm). Use the rows for inputs 1 (output 5) and 3 (output 11). What is the average rate of change from 1 to 3?

   3
3. 2.

   Tala bikes a hilly road. The table shows the km ridden. Use the rows for inputs 2 (output 10) and 4 (output 18). What is the average rate of change from 2 to 4?

   4
4. 3.

   Zee's robot collects stars. The table shows its total. Use the rows for inputs 0 (output 3) and 2 (output 13). What is the average rate of change from 0 to 2?

   5
5. 4.

   Ari fills a tub. The table shows the liters in it. Use the rows for inputs 1 (output 6) and 4 (output 18). What is the average rate of change from 1 to 4?

   4
6. 5.

   Bo's candle burns down. The rows say 20 cm at hour 2 and 8 cm at hour 5. What is the average rate of change from hour 2 to hour 5?

   -4
7. 6.

   Esme drains a bath. The rows say 30 liters at minute 1 and 12 liters at minute 4. What is the average rate of change from minute 1 to minute 4?

   -6
8. 7.

   Jun watches a snow pile melt. The rows say 45 cm at hour 0 and 20 cm at hour 5. What is the average rate of change from hour 0 to hour 5?

   -5
9. 8.

   Kira's lamp battery runs down. The rows say 21 percent at hour 3 and 12 percent at hour 6. What is the average rate of change from hour 3 to hour 6?

   -3

10. Use the table

    input s: seconds	output meters
    0	1
    1	3
    2	7
    3	13
    4	21

11. 9.

    Luz rolls a ball down a ramp, and it speeds up. The table shows the distance in meters. What is the average rate of change from second 2 to second 3?

    6
12. 10.

    Pia's toy rocket climbs. The table shows the height in meters. What is the average rate of change from second 3 to second 4?

    10