Club A is going to be 11+20x=y. Club B is going to be 15+18x=y. For both equations, x is going to be the number of months and y is going to be the total cost. We simply have to find where these lines intersect. 11+20(2)=51. 15+18(2)=51. This means after two months the cost of each will be the same. The total cost will be 51 dollars.