To find the slope (or common difference) of the arithmetic sequence represented by the number of muffins baked each day, we can calculate the difference between the number of muffins baked on each consecutive day.
- Day 1 to Day 2: \( 11 - 5 = 6 \)
- Day 2 to Day 3: \( 17 - 11 = 6 \)
The common difference (slope) of the sequence is 6.
Therefore, the answer is 6.