Acorner store sells two kinds of baked goods: cakes and pies. a cake costs $6 and a pie costs $5. in one day, the store sold 7 baked goods for a total of $40. how many cakes did they sell?

First set a Variable for the equation so make cakes your x and pies your y. then you have to make equations for the problem. Since you spent $40 and cakes cost $6 and pies cost $5, the first equation is 6x+5y=40. Since you also got seven goods the second equation would be x+y=7 (Cakes and Pies have to equal seven).  Lastly, you would put the second equation equal to x or y which could be y=7-x or x=7-y. Then you would plug it into the first equation to get x or y and then plug that answer into the second equation to get the other variable. You would get Five cakes and two pies. Hope this helps