Assuming that the $85 is before leaving a tip, you first have to find what the tip will be. Convert 18% into a decimal. You get .18, you can then multiply this by 85 to find what the tip would be. 85x.18=15.30. So now that you know the tip is $15.30 you can add that to how much they spent in the food, $85, to get the total. 15.30+85=100.30. So the total will be $100.30
