Final answer:
The expression that does not show how to calculate an 18% tip for the server at a restaurant if 'b' is the total bill is d. 0.82b, because this represents 82% of the bill instead of the tip amount.
Step-by-step explanation:
Evan wants to calculate an 18% tip for the server at a restaurant, based on the total bill, denoted as 'b'. To figure out the tip, one typically multiplies the bill amount by the percentage of the tip expressed as a decimal.
Let's examine each of the given expressions:
- a. 0.18b - This converts 18% to a decimal (0.18) and multiplies it by the bill amount, which is one correct way to calculate the tip.
- b. b * (18/100) - This takes 18%, represents it as the fraction 18/100, and multiplies it by the bill amount, which is another correct method to calculate a tip.
- c. b + (b * 0.18) - This expression adds an 18% tip calculated as b * 0.18 to the original bill amount, giving the total amount to be paid rather than just the tip.
- d. 0.82b - This represents 82% of the bill, which is not the correct way to calculate an 18% tip. Instead, it seems to be subtracting the tip from the total, which would be incorrect in this context.
Therefore, the expression that does not show how to calculate the tip is d. 0.82b.