Average speed can be calculated by __________ . Click here to access the Reference Material.

A. multiplying the total distance by the total time
Incorrect. This is not the formula for average speed. Look at your STAAR reference materials

B. subtracting the total distance from the total time
Incorrect. This is not the formula for average speed. Look at your STAAR reference materials

C. dividing the total distance by the total time
Correct!

D. dividing the total time by the total distance
Incorrect. This is not the formula for average speed. Look at your STAAR reference materials. To calculate average speed you divide the total distance by the total time.

Which of the following could be a speed measurement? Click here to access the Reference Material.

A. 3.8 meters
Incorrect. Average speed is expressed in m/s or km/hr.

B. 3.8 km/hr
Correct!

C. 3.8 seconds/meter
Incorrect. Average speed is expressed in meters/second or km/hr.

D. 3.8 hours
Incorrect. Average speed is expressed in meters/second or km/hr.

Susan walks to school every morning. She leaves her house at 7:45 a.m. and arrives at 8:15 a.m. Susan’s house is 1.5 km away. What is Susan’s average speed? Click here to access the Reference Material.

A. .33 km/hr
Incorrect. To calculate average speed you divide the total distance by the total time. You divided total time by total distance.

B. .75 km/hr
Incorrect. To calculate average speed you divide the total distance by the total time. You added the time and distance.

C. 1.5 km/hr
Incorrect. What time did you use? It took her 30 minutes to walk to school which is 0.5 hours. Remember, average speed is expressed in km/hr.

D. 3 km/hr
Correct!

What is the average speed of a sprinter that runs 100 m in 10.5 seconds? Click here to access the Reference Material.

A. 9.52 m/s
Correct!

B. .105 m/s
Incorrect. To calculate average speed, you divide the total distance by the total time. You divided total time by total distance.

C. 1050 m/s
Incorrect. To calculate average speed you divide the total distance by the total time. You multiplied total distance by total time.

D. 89.5 m/s
Incorrect. To calculate average speed you divide the total distance by the total time. You subtracted total time from total distance.

Scott runs 3 km in 30 minutes, and then he rests for 15 minutes. After his rest, he runs 2 km in 15 minutes. What was Scott’s average speed? Click here to access the Reference Material.

A. 6.66 km/hr
Incorrect. You forgot to include the 15 minutes that he rested.

B. 5 km/hr
Correct!

C. .2 km/hr
Incorrect. To calculate average speed, you divide the total distance by the total time. You divided total time by total distance.

D. .083 km/hr
Incorrect. You divided 5 km by 60 minutes. You did not convert 60 minutes to 1 hour.