To find the unit rate of pages per day, you divide the total number of pages by the number of days.
Given:
- Total pages = 40
- Total days = 4
Now, divide the total pages by the total days:
\[ \text{Pages per day} = \frac{40 \text{ pages}}{4 \text{ days}} = 10 \text{ pages per day} \]
So, the unit rate is 10 pages per day.