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05 – 04C PERCENTS

PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

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Page 1: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

05 – 04C PERCENTS

Page 2: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

PERCENT OF DECREASE OR

INCREASE

New – OldOld

Negative answer => Decrease

Positive answer => Increase

OldNew

Page 3: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

August hosted two dinner parties for his friends. Twenty guests attended the first party, and twenty-nine guests attended the second party. What is the percentage increase of the number of guests from the first party to the second party?

PERCENT OF DECREASE OR

INCREASE

New – OldOld

Negative answer => Decrease

Positive answer => Increase

Page 4: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

An item is priced at $13.24. If the sales tax is 4%, what does the item cost including sales tax?

SALES TAX

Multiply price by sales tax (decimal) $13.24 × 0.04 = $0.53(round to nearest penny)

Now, add the tax to the full price. $13.24 + $0.53 = $13.77

Page 5: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Dave rented a limousine for his wife's birthday. The hourly rate is $80. They used the limousine for 4 hours, plus Dave gave the driver a 20% tip. How much did he spend in total

for the hourly charges plus tip?

BILL PLUS TIP

First, find the total for the hourly charges.hourly rate × hours used = $80 × 4 = $320

Next, determine the tip on that total.20% of $320 = 0.2 × $320 = $64

Finally, find the total of the hourly charges plus the tip.

$320 + $64 = $384

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Tonya took out a loan to help pay for her house. She borrowed $30,000 for 15 years at a yearly simple interest rate of 5%. How much interest will she end up paying the

bank?

INTEREST

The formula for computing simple interest is shown below, where p is the principal (starting) amount, r is the interest rate (in decimal form), and t is the time (in years).

I = prtThe principal is $30,000, the time is 15 years, and the interest rate is 5%, or 0.05.

I = 

($30,000)(0.05)(15 yr)

 = 

$22,500

Page 7: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Tonya took out a loan to help pay for her house. She borrowed $30,000 for 15 years at a yearly simple interest rate of 5%. How much interest will she end up paying the

bank?

INTEREST

The formula for computing simple interest is shown below, where p is the principal (starting) amount, r is the interest rate (in decimal form), and t is the time (in years).

I = prtThe principal is $30,000, the time is 15 years, and the interest rate is 5%, or 0.05.

I = 

($30,000)(0.05)(15 yr)

 = 

$22,500

Page 8: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Tonya took out a loan to help pay for her house. She borrowed $30,000 for 15 years at a yearly simple interest rate of 5%. How much interest will she end up paying the

bank?

INTEREST

The formula for computing simple interest is shown below, where p is the principal (starting) amount, r is the interest rate (in decimal form), and t is the time (in years).

I = prtThe principal is $7,000, the rate is 3%, or 0.03, and the interest is $1,050.

Page 9: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Tonya took out a loan to help pay for her house. She borrowed $30,000 for 15 years at a yearly simple interest rate of 5%. How much interest will she end up paying the

bank?

INTEREST

The formula for computing simple interest is shown below, where p is the principal (starting) amount, r is the interest rate (in decimal form), and t is the time (in years).

I = prtThe principal is $7,000, the rate is 3%, or 0.03, and the interest is $1,050.

Page 10: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Bert is planning to open a savings account that earns 1.6% simple interest yearly. He

wants to earn exactly $288 in interest after 3 years. How much money should he deposit?

INTEREST

The formula for computing simple interest is shown below, where p is the principal (starting) amount, r is the interest rate (in decimal form), and t is the time (in years).

I = prtThe desired interest is $288, the time is 3 years, and the interest rate is 1.6%, or 0.016.

Page 11: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

Holly missed 6 of 180 school days this year. Approximately what percent of school days was Holly in attendance?

FIND A PERCENT

First, determine how many school days Holly attended.180 - 6 = 174

Next, find the percentage of school days she attended.174 ÷ 180 = 0.9666666667

= 97%

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Kathleen had a bag of candy-coated chocolates. Of the 60 candies in the bag, 20% were red, 30% were orange, 30% were green, and 20% were

blue. Of the blue ones, 10% had a damaged candy coating. Approximately how many of the blue ones had a damaged candy coating?

DAMAGED ITEMS

First, determine how many of the candies were blue.20% of 60 = 0.2 × 60 = 12

Next, find how many of the blue ones were damaged.10% of 12 = 0.1 × 12 = 1.2

Approximately 1 of the blue ones had a damaged candy coating.

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Nathan took his car in for service and repairs. He had a coupon for 10% off.

Original Prices

Labor $288.37

Parts $397.03

Other $67.18

Which amount is closest to Nathan's total costs after the 10% discount and including 7% sales tax? [Assume tax is applied after

the discount is applied.]

COUPONS

First, find the total cost for service and repairs.$288.37 + $397.03 + $67.18 = $752.58

$752.58 - 0.1($752.58) = $752.58 - $75.26

 = $677.32

Next, determine the total after the 10% discount.

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Finally, apply the 7% sales tax.

$677.32 + 0.07($677.32)

 = $677.32 + $47.41

 = $724.73

COUPONS CONT.

Page 15: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

The value of a professional basketball player's autograph rose 30% in the last year. It is now worth $364.00. What

was it worth a year ago?

PERCENTS

(1 + 30%). Convert 30% to 0.3.

$364.00 ÷ (1 + 0.3) = $280.00

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Jessica purchased a sapphire bracelet during the Jewelry Emporium's Semi-Annual Clearance Sale. If Jessica paid

$182.00 for the bracelet and the original price is $260.00, how much of a discount did she receive?

% OF DISCOUNT

Original Price - Discount =  Sale Price$260.00 - ($260.00 × p) =  $182.00

-$260.00p  =  -$78.00$260.00p  =  $78.00

p  =  $78.00 ÷ $260.00p  =  0.3p  =  30%

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Molly is having her birthday party at Pizza Party Palace. The costs involved are listed below. Pizza Party Palace

requires a 20% deposit prior to the date of the event. If the deposit has been paid, how much is still owed for Molly's

party?

DEPOSIT, HOW MUCH IS STILL OWED

• Food & Drink$20

0

• Game Tokens$10

0• Other $60

First, find the total of all party costs.$200 + $100 + $60 = $360Next, find 20% of $360.20% of $360 = 0.2 × $360 = $72

$360 - $72 = $288

Page 18: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

• 6-ounce $9.95• 8-ounce $12.95

•11-ounce

$15.95

MEALS AND GRATITUITY

Brad had a small gathering at a local steakhouse. The steakhouse offers three dinner platters which vary by size and price. They ordered 4 of the 6-ounce platters, 2 of the 8-ounce platters, and 2 of the 11-ounce platters.Steak Platter Prices

If a gratuity of 18% was added to the bill, which of the following is closest to the total of the steak platters and gratuity, ignoring sales tax?

4($9.95) + 2($12.95) + 2($15.95)

$39.80 + $25.90 + $31.90 = 

 = 

$97.60

First, find the total cost for all dinner platters.

Page 19: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

MEALS AND GRATITUITY

Brad had a small gathering at a local steakhouse. The steakhouse offers three dinner platters which vary by size and price. They ordered 4 of the 6-ounce platters, 2 of the 8-ounce platters, and 2 of the 11-ounce platters.Steak Platter Prices

If a gratuity of 18% was added to the bill, which of the following is closest to the total of the steak platters and gratuity, ignoring sales tax?

Next, determine the 18% gratuity.18% of $97.60 = 0.18 × $97.60

$17.57

$17.57

Finally, find the sum of the dinner platters plus the gratuity.

$97.60 + $17.57 = $115.17

Page 20: PERCENT OF DECREASE OR INCREASE New – Old Old Negative answer => Decrease Positive answer => Increase Old New

In his free time, Gary spends 12 hours per week on the Internet and 7 hours per week playing video games. If Gary

has five hours of free time per day, approximately what percent of his free time is spent on the Internet and playing

video games?

% OF TIME

First, find the total time Gary spends on the Internet and playing video games per week.12 + 7 = 19

Next, determine how much total free time he has each week.5 × 7 = 35

Finally, determine what percent of his free time is spent on the Internet or playing video games.19 ÷ 35 = 0.5428571429

Gary spends approximately 54% of his free time on the Internet and playing video games.

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Brian has reduced his cholesterol level by 14% by following a strict diet and regular exercise. If his original level was

300, what is his cholesterol level now?

PERCENTS

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Sandy works at a clothing store. She makes $9 per hour plus earns 15% commission on her sales. She worked 70

hours over the last two weeks and had a total of $1,822 in sales before taxes.

Which of the following is closest to how much she will earn in hourly wages and commission for those two weeks?

COMMISSION

First, determine Sandy's earnings based on her hourly wage.hours worked × hourly wage = 70 × $9 = $630Next, determine her commission on her total sales.15% of her total sales = 0.15 × $1,822 = $273.30Finally, find the sum of her hourly wages plus commission.$630 + $273.30 = $903.30

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THE END