Finding Percent

Think of percent as being the part of a whole

% = Part x 100Whole

Divide the part by the whole.

This will give you a decimal.

Then convert to a percent by either:1. Multiplying the decimal by 1002. Moving the decimal 2 places to the right

Example: Leeds has a total of 390 students. 125 of them attended the football game. What percent attended the game?

Percent = Part = 125 Whole 390

= 0.3205 ---- convert to a percent = 32.05%

We have 16 students in the class. 14 of the students are seniors.

• What percent of the class is seniorsPercent = Part = 14

Whole 16

= 0.875Convert to a percent= 87.5%

During basketball season, James attempted 70 shots and made 28 of them.

• What percent of the shots did he make?Percent = Part = 28

Whole 70

= 0.4Convert to a percent= 40%

Classwork

• Page 428, #35-41

Percent Increase

• Percents are often used for comparing changes, such as increases or decreases in sales, population, or production

Percent Increase = Amount of ChangeOriginal Amount

Example

• Find the percent change from 120 to 165

• Original amount is 120; • The amount of change is 165-120 = 45

• Percent change = 45 = 0.375 = 37.5%120

• Last year, Leeds had an enrollment of 386 students. This year the enrollment is 419. What is the percent increase?

Using Percents to Calculate Discounts and Commissions

Discount – a price reduction offered by a business to attract customers and to

reduce inventory

Examples:All Dockers Pants 15% off!All Jackets 20% off!Take 50% off all Spring Merchandise!

How to calculate the discount

Example:• Original Price is $40. It is on sale for 15% off.

a. What is the discount amount?b. What is the new sale price?

a. Discount amount = discount rate x original price = .015 x $40 = $6.00 this is the amount of the discount

b. New Sale Price = Original Price – Discount Amount = $40 - $6 = $34.00

Sometimes, stores will have discounts on top of discounts…

All spring shirts are 40% off.

From 7-noon, take AN ADDITIONAL 20% off all sale merchandise

Most people would add the two discounts to get 60%, but this is incorrect.

A shirt regularly sells for $30.00

• The shirt is on sale for 40% off.• Until noon, you can take an additional 20% off the sale

price.

• The first 40%: 0.40 x 30 = $12, so the sale price would be $30 - $12 = $18.

• THEN, take the additional 20% off the sale price: $18 x 0.20 = $3.60.

• That makes the final sale price $18.00 - $3.60 = $14.40

Commission – an amount paid to an employee based on performance

• Examples: Car salesmen make a commission for each car sold.

• Real estate salespeople make a commission on the houses they sell.

• Commission is usually calculated as a percent of the sale price.

John sells office equipment and is paid 5% commission on his total sales. If he had sales of $14,000 last week, how much commission did

he make?

Commission earned = Commission rate x Sales

= 0.05 x 14,000

= $700 commission earned

Jenny sells real estate. She makes 6% commission on sales. Last week she sold a

house for $135,000. How much commission did she earn?

• Commission earned = Comm. Rate x Sales

• 0.06 x 135,000 = $8,100

Cameron makes 7% commission on sales. What was his weekly earnings

based on the sales for last month?

WEEK SALES1 $8,6002 $9,6003 $7,5004 $10,900

COMMISSION EARNED

Sales Tax

• An extra amount that is paid on most purchases.

• State, city and county governments usually have a tax:– Example: Alabama 4%, Jefferson County 2%,

Leeds 3%. These add to a total of 9%.

You purchase items at Wal Mart totaling $32.80.The sales tax rate is 9%

• How much will the tax be, in dollars?

• What will be the total purchase price?

Classwork

• Page 428; #42-50