Why??

Percents are all around us!Sales and discounts shoppingSales TaxIncome TaxesTips on restaurant billsEtc…

When doing problems with % remember all %’s can become decimals!

The How! Convert all percentages to decimals

i.e. 85% = 0.85 150% = 1.50

Multiply the original cost of an item by the percentage to find the cost of the increase or decrease

Add (taxes, markup, etc) or Subtract (sale, discount, etc) by the amount to find the final price.

Example #1

The original cost of a sweater is $32.00. What is the price after a 20% discount?

20% = 0.2032.00 * 0.20 = 6.40

$32.00 - $6.40 = $25.60

Example #2

A $20,000 car is on sale for 15% off. What is the sale price of the car?

15% = 0.1520,000 * 0.15 = 3,000

20,000 – 3,000 = $17,000

Example #3

You and your friends go to Applebee’s for dinner and spend $45.23. If you leave a 18% tip, what is your total cost?

18% = 0.1845.23 * 0.18 = 8.14

45.23 + 8.14 = $53.37

Example #4

There is a 7.5% sales tax on a $240 TV. How much should you pay?

7.5% = 0.075240 * 0.075 = 18

240 + 18 = $258

Example #5

Best Buy has a $199 phone on sale for 15% off. Then you have to pay 7% sales tax. How much will it cost?

15% = 0.15 199* 0.15 = 29.85199 – 29.85 = $169.15

7% = 0.07 169.15 * 0.07 = 11.84169.15 + 11.85 = 180.99

Example #6

A $550 computer is on sale for 25% off. How much will the computer cost after a 8.5% sales tax?

25% = 0.25 550 * 0.25 = 137.50550 – 137.50 = 412.50

8.5% = 0.085 412.50 * 0.085 = 35.06

412.50 + 35.06 = $447.56