To determine if the relationship between the time walking and the calories burned is proportional, we need to check if the ratio of calories burned to time walking remains constant.
Let's calculate the ratios:
- For 20 minutes: 100 calories / 20 minutes = 5
- For 30 minutes: 150 calories / 30 minutes = 5
- For 40 minutes: 200 calories / 40 minutes = 5
- For 60 minutes: 300 calories / 60 minutes = 5
- For 80 minutes: 400 calories / 80 minutes = 5
Since the ratio (calories burned per minute) remains constant at 5 for all time intervals, the relationship is proportional.
Thus, the correct response is:
The relationship is proportional.