To determine the correct units for the average speed of a long walk, we need to understand the relationship between distance and time.
1. Identify the quantities involved:
- Distance traveled: This is measured in inches (in).
- Time elapsed: This is measured in hours (hr).
2. Conceptualize the formula for average speed:
- Speed is typically calculated as Distance divided by Time.
- Mathematically, this relationship is expressed as:
[tex]\[
\text{Speed} = \frac{\text{Distance}}{\text{Time}}
\][/tex]
3. Substitute the units into the formula:
- Distance is given in inches (in).
- Time is given in hours (hr).
- Thus, substituting these units into the speed formula, we get:
[tex]\[
\text{Speed} = \frac{\text{inches}}{\text{hours}}
\][/tex]
4. Express the units mathematically:
- The units of speed will therefore be:
[tex]\[
\frac{\text{ in }}{\text{ hr }}
\][/tex]
5. State the units in words:
- The units of average speed are "inches per hour".
Based on this understanding, the correct answer is:
[tex]\[ \text{A. } \frac{\text{ in }}{\text{ hr }} \][/tex]
