So if he paid $240 for 12 tires.
That means if he brought 3 tires, he bought it for 240/4 = 60, and that means he bought each tire for 20 becase 60/3= 20
We are dividing by 4 because 12/4 = 3
And that means he sold the two tires for 60, and 1 tire sold for 30 because 60/2 = 30
So if he buys one tire for 20, and sells it for 30, he is making $10 profit for each tire.
So how much profit did he make on 12 tires?
12 x 10 = 120
So made a

profit.