a restaurant customer left $2.20 as a tip. the tax was 7% and the tip was 20% of the after tax cost. which information is not needed to compute the bill after tax and tip? what was the total bill?

If you take the 20% and multiply it by the tip that was given (2.20), you would get 11$. The total bill including tip would be $13.20. The tax percent was unneeded since we already received the information that the tip was a percentage of the cost AFTER the tax.