To find the mode of the boxes of cookies sold, we need to identify which number appears most frequently in the data.
From the information provided, the number of boxes sold over the past 6 days appears to be:
- Thursday: 0 boxes
- Friday: 10 boxes
- Saturday: 20 boxes
- Sunday: 30 boxes
- Monday: 40 boxes
- Tuesday: 50 boxes
Since each of these numbers is unique and appears only once, there is no number that appears more frequently than the others.
Thus, there is no mode in this data set.