Tax, tip, and the little extra

The diner adds tax. You add a tip. A coupon takes a percent off before any of that.

In plain words

Sales tax is extra added to a price. At a stated rate of 8.25%, tax on $40 is 40 × 0.0825 = $3.30. The total with tax is $40 + $3.30 = $43.30, or 40 × 1.0825. Use the rate given in the question.

A tip is extra you choose to leave for the person who brought the food. Same move as tax. 20% of $40 is 0.20 × 40 = $8. Then add it on.

A coupon gives a discount: money taken off the price. Read the question to see whether the discount comes before tax and which price the tax uses. For example, if an $80 item is $12 off before tax, calculate tax on $68.

Interest is extra money paid for using money. A bank may pay you interest on savings. When you borrow money, you may pay interest as an extra cost. Simple interest uses the starting amount each year. With yearly compound interest, the next year also earns interest on the interest already added. The Money topic shows both with numbers.

Examples

Try it. Then open the steps.

Example 1 of 5

The diner

Food costs $32. Tax is 8%. Tip is 15% of the food (before tax). What is the total?

Example 2 of 5

Simple vs compound

You put $200 in the bank at 5% interest per year for 3 years. Find the interest earned and the final balance (the total money in the account). Do it with simple interest. Then do it with interest compounded yearly (each year's interest is added on and also earns interest). Round money to the nearest cent.

Example 3 of 5

Nachos at the match

Snack cart, soccer night

Food is $16. Tax is 8.25% on the food. Tip is 15% on the food only. Total?

Example 4 of 5

Mall coupon, then tax

The register

An $80 jacket is $12 off, then 8% tax is added to the discounted price. What do you pay?

Example 5 of 5

Ice cream and the 8.25%

The shop, two cones

Two cones cost $9. Tax is 8.25%. What is the total?

Things to watch for

Easy to miss: Taxing the tip, or tipping on the tax, when the problem did not say to.
Do this: Do only what the sentence asks. If it says tax on the food, tax the food.
Easy to miss: Using 8% when the rate is 8.25%. That 0.25% is real money on a big bill.
Do this: 8.25% = 0.0825. Write it down.

22 problems · Camp, Trail, Summit

Practice Solution key