1. The problem asks for the maximum value shown in the box-and-whisker plot for blueberry pies sold each day. 2. In a box-and-whisker plot, the maximum is represented by the rightmost point of the right whisker. 3. According to the description, the right whisker ends at 8. 4. Therefore, the maximum number of blueberry pies sold in a day is $8$. **Final answer:** $8$