The Sanchez family had dinner at their favorite restaurant. A 9% sales tax was added to their bill. Amy paid the bill with a $10 gift certificate plus $30.60. How much did the family's dinner cost before tax? Round your answer to the nearest penny. Hint: Use the equation P + rP = T,
where P is the price before tax, r is the sales tax rate, and T is the total price, including tax.
The sales tax rate is 8.2%. Estimate the sales tax on a computer that costs $550.