Answer:
20
Explanation:
Order the numbers from smallest to largest, then cross one number off until you have one or two numbers left.
If there is an EVEN number of numbers(like this one): there will be two numbers left, therefore you add those two numbers together, then divide by two.
If there is an ODD number of numbers: there will be one number left, therefore that is your answer!
Hope this helps!
-PusheenDaCat1017