Torri had
$20 to buy a birthday present for his day he decided to buy a dvd for $18 the sale tax is 7% does she have enough money explain your reasoning

Yes, she will because 
E.X.:
Divide the sales tax percentage by 100 (or simply move the decimal point two places to the left) to get the decimal equivalent of the rate. So if the tax rate was 7.375%, the decimal equivalent would be .07375.Multiply the taxable price by the decimal equivalent of the rate. For example, if the taxable price was $50.00 and the rate was 7.375%, then the sales taxes would be $3.69 ($50 x .07375 = 3.6875 = $3.69 when rounded to the nearest cent). Hopes this helps if not I can explain it better.