Multi Tiered Commission Function

Good Morning,

I have been working on trying to create a multi tiered commission table and I am having no luck writing the function. The commission breaks are 0-9 no commission, 10-19 is times 10 of the total appointments from 10-19, 20-29 is times 20 of the total appointments from 20-29, and the final is 30-higher is 30 times the total number appointments after 30. So if the person set 31 appointments they would get $360. If the person set 22 they would get $140.

Thanks
Brett