Brad and Don went to the mall together. Brad spent $18 on food. Don spent twice the amount of money that Brad spent.
a) Write an algebraic equation to express how much Don spent and solve the equation you made.
b) Brad's sister had gone to the mall the day before and spent 30% of what Don did. How much did she spend?
c) If the tax rate was 13% how much of what Don and Brad spent was for tax?