Carol, Leo, and Jed eat dinner at a restaurant. They know that they will pay a 10% sales tax and they plan to leave a 15% tip. Write an expression to represent each method for calculating their total below. The original cost of the meal, before tax or tip, was $20. Will these methods result in the same total? Explain. ● Jed thinks it will be easier to do it in separate steps. He wants to calculate the tax first and add it, then add 15% of that new total for the tip. ● Leo agrees with Jed, but thinks that they should calculate the tip first, then add 10% of the new amount. Leo thinks he will save them money by calculating 15% of a smaller amount.

Question

Carol, Leo, and Jed eat dinner at a restaurant. They know that they will pay a 10% sales tax and they plan to leave a 15% tip. Write an expression to represent each method for calculating their total below. The original cost of the meal, before tax or tip, was $20. Will these methods result in the same total? Explain. ● Jed thinks it will be easier to do it in separate steps. He wants to calculate the tax first and add it, then add 15% of that new total for the tip. ● Leo agrees with Jed, but thinks that they should calculate the tip first, then add 10% of the new amount. Leo thinks he will save them money by calculating 15% of a smaller amount.

Answer 1

Jed's method:

Tax amount = 10% of $20 = $2
Total with tax = $20 + $2 = $22
Tip amount = 15% of $22 = $3.30
Total = $22 + $3.30 = $25.30

Leo's method:
Tip amount = 15% of $20 = $3
Total with tip = $20 + $3 = $23
Tax amount = 10% of $23 = $2.30
Total = $23 + $2.30 = $25.30

Both methods result in the same total of $25.30. This is because the order in which the tax and tip are calculated does not affect the final amount.