In most cases, the Card Act prevents credit card companies from raising the interest rate on an existing balance. In other words, if your rate goes up, the new rate will apply only to new charges going forward. But if you get hit with a penalty APR, your issuer is permitted to apply it to outstanding balances.
She can buy 2 bags of fruit (adds up to 9.50) and of course the box of crackers that is 3.5, in total it adds to $13. So the answer is she can buy 2 bags of fruit.
