So, when doing this kind of problems, the first thing that we would want to do is to add up (all) the numbers first, and by doing this, it would look like the following:
[tex]5+5+ 8+10=28[/tex]
Then, we would then divide it by how many numbers they are.
[tex]\boxed{28\div4} \ =7[/tex]
Your answer: 7