Wendy drives a car 110 kilometers per hour. What is this rate, in miles per hour, to the nearest tenth?
The Correct Answer and Explanation is:
To convert Wendy’s speed from kilometers per hour (km/h) to miles per hour (mph), we use the conversion factor between kilometers and miles. The standard conversion is:
[
1 \, \text{kilometer} = 0.621371 \, \text{miles}
]
Step-by-Step Conversion
- Write down the given speed in km/h:
Wendy drives at a speed of 110 km/h. - Use the conversion factor:
To convert the speed from kilometers to miles, multiply the distance in kilometers by the conversion factor 0.621371 miles per kilometer. This will give the equivalent speed in miles per hour.
[
110 \, \text{km/h} \times 0.621371 = 68.35081 \, \text{miles per hour}
]
- Round to the nearest tenth:
The calculated speed in miles per hour is approximately 68.35081 mph. Rounding this to the nearest tenth gives:
[
68.4 \, \text{mph}
]
Final Answer:
Wendy’s speed is 68.4 miles per hour when rounded to the nearest tenth.
Explanation:
The process of converting kilometers to miles requires understanding the ratio between the two units of distance. The ratio 1 kilometer = 0.621371 miles is a standard value used for such conversions. By multiplying Wendy’s speed in kilometers per hour (110 km/h) by this conversion factor, we obtain the equivalent speed in miles per hour (mph).
This type of conversion is common in everyday scenarios, such as traveling internationally or using different systems of measurement (metric vs. imperial systems). For example, speed limits on highways are often posted in miles per hour in countries like the United States, whereas many other parts of the world use kilometers per hour. Converting between these two units is a vital skill for understanding travel speeds when crossing borders or reading road signs in different countries.