You've just enjoyed a delicious meal at a restaurant with your friend, The cost of the meal before tax a tip is $35.10

(1) Suppose tax is 15% of the total cost. Calculate the dollar amount of tax, and total cost including tax.

(2) If you want to tip the server an additional 20% after tax, how much would you pay in total?

(3) How much change would you receive if you paid with a $100 bill?

(4) Suppose you are a server. In general, when would you rather receive a $20 tip instead of 20% of your bill? Justify your thinking.