Let's do some practice problems.

### Practice Problem 1

What is the average speed of a helicopter that flies 50 km in 20 minutes and then 30 km in 10 minutes?

Step 1: Determine Total Distance

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What is the average speed of a helicopter that flies 50 km in 20 minutes and then 30 km in 10 minutes?

50 km + 30 km = 80 km

Step 2: Determine Total Time

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What is the average speed of a helicopter that flies 50 km in 20 minutes and then 30 km in 10 minutes?

20 minutes + 10 minutes = 30 minutes

Remember, speed is expressed as km/hr or m/s. In this problem, time is measured in minutes, so you must convert to hours.

There are 60 minutes in 1 hour, so the conversion would look like the problem below.

The minutes cancel out, and we are left with 30 over 60 30 60 hours, or 0.5 hours.

Step 3: Calculate the Average Speed

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Average Speed = Total Distance over Total Time Total Distance Total Time
Average Speed = 80 km over .5 hr 80 km .5 hr
Average Speed = 160 km/hr

### Practice Problem 2

What is the average speed of a lizard that runs 100 meters in 40 seconds and then runs an additional 50 meters in 20 seconds?

Step 1: Determine Total Distance

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What is the average speed of a lizard that runs 100 meters in 40 seconds and then runs an additional 50 meters in 20 seconds?

100 m + 50 m = 150 m

Step 2: Determine Total Time

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What is the average speed of a lizard that runs 100 meters in 40 seconds and then runs an additional 50 meters in 20 seconds?

40 seconds + 20 seconds = 60 seconds

Step 3: Calculate the Average Speed

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Average Speed = Total Distance over Total Time Total Distance Total Time
Average Speed = 150 m over 60 s 150 m 60 s
Average Speed = 2.5 m/s

### Practice Problem 3

A snail moves 100 meters in 2 hours. What is his average speed?

Step 1: Determine Total Distance

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A snail moves 100 meters in 2 hours. What is his average speed?

Remember, speed is expressed in km/hr or m/s. To complete this problem, we will need to convert the meters to kilometers or hours to seconds. It is easier to convert meters to kilometers.

100 meters = .1 km

Step 2: Determine Total Time

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A snail moves 100 meters in 2 hours. What is his average speed?

Step 3: Calculate the Average Speed

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Average Speed = Total Distance over Total Time Total Distance Total Time
Average Speed = .1 km over 2 hours .1 km 2 hours
Average Speed = .05 km/hr