Information about the age of participants in a robotics competition is below: A box plot titled "Age of Participants" and labeled "Age" uses a number line from 10 to 35 with primary markings and labels at 10, 15, 20, 25, 30, and 35. The box extends from 13 to 31 on the number line. A line in the box is at 16. The whiskers end at 11 and 33. The middle 50% of the data is between what two numbers?