Let's solve the problem together. First, we need to calculate Courtney's walking rate (miles per hour) for both days and verify if they are consistent to assume a constant rate.

Step 1: Calculate her walking rate for both days

Yesterday:

• Distance = 2.4 miles
• Time = 45 minutes = $\frac{45}{60} = 0.75$ hours
• Walking rate = $\frac{2.4}{0.75} = 3.2$ miles per hour

Today:

• Distance = 2.8 miles
• Time = 52.5 minutes = $\frac{52.5}{60} = 0.875$ hours
• Walking rate = $\frac{2.8}{0.875} = 3.2$ miles per hour

Since the walking rates for both days are the same ($3.2 \, \text{mph}$), we can conclude that Courtney walks at a constant rate.

Step 2: Analyze the question

The question asks about the relationship between walking time and distance. If Courtney walks at $3.2 \, \text{mph}$, then:

• Walking for 1 hour covers $3.2 \, \text{miles}$
• Walking 1 mile takes $\frac{1}{3.2} \approx 0.3125$ hours (or about 18.75 minutes)

Now evaluate the options:

• A: "An additional 3.2 hours of walking is associated with an additional mile walked."
  Incorrect. Walking 1 mile takes much less time (about 0.3125 hours).

• B: "An additional hour of walking is associated with an additional 3.2 miles walked."
  Correct. Walking for 1 hour covers exactly $3.2 \, \text{miles}$.

• C: "An additional hour of walking is associated with an additional 0.7 mile walked."
  Incorrect. 1 hour corresponds to 3.2 miles, not 0.7 miles.

• D: "An additional 0.7 hour of walking is associated with an additional mile walked."
  Incorrect. Walking 1 mile takes 0.3125 hours, not 0.7 hours.

Final Answer:

B. An additional hour of walking is associated with an additional 3.2 miles walked.

Would you like further details or help understanding any step?

Expanding Questions:

1. How can you calculate the walking rate from time and distance?
2. What is the relationship between time, distance, and speed in general?
3. If Courtney walked for 2 hours, how far would she travel?
4. How do you convert minutes into hours accurately?
5. Why is it important to verify the assumption of a constant walking rate?

Tip:

Always double-check units (e.g., converting minutes to hours) to ensure accurate calculations.