So think of it like this she starts off $32 negative and subtract 3 from each box of cards she makes . So each box of cards she will make $8 that being said
32/8 =4 (it will take 4 box of cards to pay off her booth expense).
Sales would be 11x 4 =44
Expenditures would be 3x4 =32 (the amount used to make cards ) +32(the amount paid for the booth)
Which in total would be $64