To determine if the relationship between time walking and calories burned is proportional, we check if the ratio of calories burned to time walking is constant for all the values in the table.
Calculating the ratios:
- For 20 minutes: \( \frac{100 \text{ calories}}{20 \text{ minutes}} = 5 \)
- For 30 minutes: \( \frac{150 \text{ calories}}{30 \text{ minutes}} = 5 \)
- For 40 minutes: \( \frac{200 \text{ calories}}{40 \text{ minutes}} = 5 \)
- For 60 minutes: \( \frac{300 \text{ calories}}{60 \text{ minutes}} = 5 \)
- For 80 minutes: \( \frac{400 \text{ calories}}{80 \text{ minutes}} = 5 \)
Since the ratio of calories burned to time walking is constant (all equal to 5), the relationship is proportional.
Thus, the correct response is:
The relationship is proportional.