Casey uses some of his savings on batting practice. the cost of renting a batting cage for 1 hour is $6. he rents a cage for 9 hours in each of two months. what is the change in casey's savings after 2 months?

I'm assuming that he rented the batting cage just once in those two months because the problem does not say anything about using the batting cage more than once. So with this assumption, the change in Casey's savings after 2 months is less 108 dollars. In order to get this, first I multiplied 6 dollars to 9 hours to get how much he spent in a batting cage in the first month. The answer to that is 54 dollars. Since he did that for 2 months, then 54 times 2. This will result in 108 dollars. 

What exactly is your question?