Her new balance is now $-37.27. If each book costs 12.99 dollars each, and she is trying to buy 3, it will cost her $38.97. Since she doesn’t have enough money, they charge her an extra $20. If you add both values together, you get $58.97. Remember she has $21.70 in her account, so we subtract $21.70 by 58.97, and we get -37.27 dollars. She is in debt with a current balance of -$37.27.
