To determine how many minutes Margaret walks in 28 days if she walks 30 minutes per day, you can multiply the daily walking time by the number of days:
\[ \text{Total Minutes} = \text{Daily Minutes} \times \text{Number of Days} \]
Given:
- Daily Minutes = 30 minutes
- Number of Days = 28
Calculating:
\[ \text{Total Minutes} = 30 , \text{minutes/day} \times 28 , \text{days} = 840 , \text{minutes} \]
Therefore, Margaret walks 840 minutes in 28 days.
The correct response is 840 minutes.