When we do unit conversions for speed, we have units in the numerator and denominator that we need to change to what we want. The process is exactly the same; we just need to watch two sets of units. The following video will explain how to do this by showing an example problem:

Unit Conversions for Speed

Video Source (03:56 mins) | Transcript

Steps for Speeds Unit Conversions

- Start with what you know. (On top and bottom.)
- Determine what you want to get in the end. (On top and bottom.)
- Determine what conversion factor(s) to use. You will need more than one. (At least one for the top and one for the bottom.)
- Multiply by 1 in the form of the conversion factor that cancels out the unwanted units.

## Additional Resources

- Khan Academy: Intro to Rates (05:29 mins; Transcript)
- Khan Academy: Solving Unit Rate Problem (02:30 mins; Transcript)
- Khan Academy: Worked Example: Rate Problem (04:12 mins; Transcript)
- Khan Academy: Multiple Rates Word Problem (06:27 mins; Transcript)
- Khan Academy: Finding Average Speed or Rate (13:14 mins; Transcript)

### Practice Problems

1. Alice was roller-skating down the street at a speed of 9 kilometers per hour (km/h). Use the fact that 1 kilometer is approximately equal to 0.6214 miles to convert this speed to miles per hour (mph). Round your answer to the nearest tenth.1 km = 0.6214 mi

Note that mph or miles per hour is the same as miles/hour or \(\dfrac{\text{miles}}{\text{hour}}\).

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Solution

1 mi = 1.609 km

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Solution

1 mi = 1609.344 m

1 h = 60 min

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Solution

1 m = 3.2808 ft

1 min = 60 sec

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Solution

1 m = 3.2808 ft

1 min = 60 sec

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Solution

1 km = 1000 m

1 min = 60 sec

1 hour = 60 min

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Solution

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