They each made 3600 dollars.
I found this by taking the total amount the house is worth ($120,000), and multiplied it by the commission Tanner and Brad get (6% or 0.06). This looks like this:
120,000 x 0.06
Then when you multiply that together you get 7,200. With this number you simply divided it by two to equally divide the money between two people:
7,200 / 2
=
3,600
Tanner and Brad each receive $3,600 dollars in commission for the house!
Hope this helps! :)