1. **State the problem:** We need to find the median number of books on a shelf based on the histogram data. 2. **Understand the data:** The histogram shows the number of shelves for each range of books: - 0-9 books: 0 shelves - 10-19 books: 5 (blue) + 3 (pink) = 8 shelves - 20-29 books: 5 shelves (blue) - 30-39 books: 3 shelves (pink) - 40-49 books: 3 shelves (pink) - 50-59 books: 6 shelves (blue) 3. **Calculate total shelves:** $$8 + 5 + 3 + 3 + 6 = 25$$ shelves in total. 4. **Find the median position:** The median is the middle value when all shelves are ordered by number of books. Since there are 25 shelves, the median is the $$\frac{25 + 1}{2} = 13^{th}$$ shelf. 5. **Locate the 13th shelf in the ordered data:** - Shelves 1 to 8: 10-19 books - Shelves 9 to 13: 20-29 books The 13th shelf falls in the 20-29 books range. 6. **Choose the median number:** From the options (17, 24, 31, 43, 58), the number in the 20-29 range is 24. **Final answer:** The median number of books on a shelf is **24**.