Percent Application Packet

1

Unit 3A – Percent Applications

Unit 3A Goals:

Established Goals:

7.RP.3 Use a ratio and rate reasoning to solve real-world and mathematical problems by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations.

2

Percent Test Topics

*Vocabulary reference sheet

*Converting fractions, decimals, and percents

*Solving percent proportions

*Solving percent proportions in word problems

-discount

-sales tax

-tip/gratuity

-commission

*Using the simple interest formula

3

How Can I Be Successful On My Test?

_____

Read over the Test Topics given to me one week before the test.

_____

Look in my notes for the Test Topics and read them over.

_____

Find examples of the Test Topics in my notes and try some of the examples

again/complete any examples that were not done.

_____

Re-take the quiz from the unit, if there was one.

_____

Print blank copies of notes/practice problems from the webpage and complete

them. Check my answers on the webpage.

_____

Review the rules for the unit concepts and unit vocabulary

_____

Use online sources such as IXL or quizlet or Kahoot.

_____

Come to one or more extra help sessions to review the

Test Topics.

_____

Ask a friend or family member to review the Test Topics with me.

Predicted Test Score: _______________

4

KEY VOCABULARY:

1. Amount of

Discount/Sale

– Money

saved

on an item. (

A decrease in price

.)

2. Rate of Discount/Sale

– The percent of the money saved, ex. 20% off

3. Sales Price

– Regular price

MINUS

the amount of the discount

4. Amount of

Sales Tax

– Extra money

paid

on an item (

An increase in price

.)

5. Rate of Sales Tax

– The percent of the money you will spend, ex. 5%, 4.5%

6. Total Cost

– Regular price

PLUS

the amount of sales tax

7.

Commission

– Money a salesperson

earns

based on

how much they sell

. For

example, a car salesman works on commission. That is why they try to sell your

parents lots of extra features in the car, like DVD players, a sun roof, and

navigation systems. The more money the car costs, the more commission a

salesperson earns.

8. Rate of Commission

– The percent of the commission a salesperson earns.

for example: 4% commission

9.

Gratuity

–

Money

added

on to the cost of a service, for example a tip given

to a waiter.

10. Rate of Gratuity –

The percent of gratuity you will add on, ex. 18%

11.

Markup

– The

difference

between the selling price and the original cost of

an item

5

When interpreting word problems to set up proportions, use this guide:

BASE (Starting Value) (WHOLE)

Original Price

Regular Price

Amount of Merchandise Sold

Amount of the Service

Original Cost

Part (what you add or subtract) (PART)

Amount of discount/sale

Amount of sales tax

Amount of commission

Amount of gratuity

Amount of mark-up

Percent % (p)

Rate discount

sale

Rate of sales tax

Rate

commission

Rate of gratuity

Rate of mark-up

Using the Percent Proportion

To represent “ a isp percent of b”, use the proportion

a

b =

p

100

100

p

whole

part



100

%



of

is

13

.

Interest

– The ($) amount of interest that is owed or earned.

14

. Principal (P)-

The amount of money that was borrow, saved or invested.

15.

Rate (R)

- The percent of interest.

16.

Time (T)

- Time is

always

in

years

.

6

AIM: SWBAT convert fractions and decimals to a percent and vice versa.

DO NOW: Using your calculator, simplify each FRACTION.

1)

10028 = 2) 33 = 51 3) 5719 = *4) 100125 =

Using your calculator, change each fraction into a decimal. (Divide the numerator by denominator)

5) 5

3 = 6)

208 = 7) 253 =

8) What type of decimals are numbers 5-7? (circle one) terminating or repeating

9)

91 = 10) 97 = 11) 9928 =

12) What type of decimals are numbers 9-11? (circle one) terminating or repeating

Change each terminating decimal into a fraction in SIMPLEST FORM. (Use the place value as the denominator.)

13) 0.4 = 10

4 ₌

14) 0.36 =

15) 0.375 =

7

CLASSWORK:

**PERCENTS are based on the number 100**

Change each

decimal or fraction into a percent

. *

1) 0.05

2)

8 3

3) 21.4

4)

9 5

Change each

percent into a decimal

.

Change each

percent into a fraction

in SIMPLEST FORM. Use the following

steps to guide you:

1.

Put the percent over 100

2.

Simplify using

the

a

button on your calculator

You Try: Change each percent into a fraction in SIMPLEST FORM, and into a decimal.

PERCENT FRACTION DECIMAL

4)

40%

5)

56.25%

8

COMPLETE THE FOLLOWING TABLE

(Use your calculator and your calculator knowledge!!)

To

change

a number

to

a

percent

you

MULTIPLY

the number by

100

To

change

a

percent

to

a

decimal

or fraction you

DIVIDE

the percent by

100

FRACTION DECIMAL PERCENT

.45

4

3

9 HOMEWORK – CHANGING FRACTIONS & DECIMALS TO PERCENTS

Change each fraction or decimal into a percent.

*To

change

a number

to

a

percent

you

MULTIPLY

the number by

100

*

1)

0.05

0.24

3)

8

3

50

43

Change each percent into a fraction AND a decimal in SIMPLEST FORM.

PERCENT FRACTION DECIMAL

9) 60%

10) 35%

11) 18%

12) 104%

Remember:

*Change each

percent into a fraction

in SIMPLEST FORM. Use the following

steps to guide you:

1.

Put the percent over 100

2.

Simplify using

the

a

button on your calculator

10

AIM: SWBAT convert fractions and decimals to a percent and vice versa. DO NOW:

1) When you rewrite a number as a percent, you _______________ that number by 100.

2) When you rewrite a percent as a decimal or fraction, you ___________ that number by 100.

Write the decimal or fraction as a percent.(multiply by 100)

3) 0.28 ₄₎

8

5 5) 34.6

Write the percent as a decimal AND as a FRACTION in simplest form.(divide by 100)

Decimal Fraction

6) 16%

7) 47.35%

COMPLETE THE FOLLOWING TABLES (Use your calculator and your calculator knowledge!!)

To change a number to a percent you MULTIPLY the number by 100

To change a percent to a decimal or fraction you DIVIDE the percent by 100

11

CHALLENGE:

12

Homework – Decimals, Fractions & Percents

Change each decimal or fraction into a percent. (multiply by 100)

1) 0.16 ₂₎

16 15

3) 8

7 4) 0.009

Write the percent as a decimal AND as a FRACTION in simplest form.

*to change a percent to a decimal divide by 100*

*to change a percent to a fraction, put it over 100 and simplify using

the abc button on your calculator*

Decimal Fraction

5) 94%

13

AIM: SWBAT solve problems using the percent proportion.

DO NOW:

1) When you rewrite a number as a percent, you _______________ that number by 100.

2) When you rewrite a percent as a decimal or fraction, you ___________ that number by 100.

Write the percent as a decimal AND as a FRACTION in simplest form.

PERCENT DECIMAL FRACTION

3) 18%

4) 12.25%

Using the Percent Proportion

To represent “ a isp percent of b”, use the proportion

a b =

p

100 _wholepart ₁₀₀p _ofis ₁₀₀%

Where a is part of the base b and p%, or _{100 , is the percent.} p

1) 15 is what percentof 90? 2) What number is 10% of 56.

14

Define a variable and set-up a proportion for each problem. Write your final answer in a complete sentence.

1) Rossana is planting in her garden. Out of the 240 newly planted seedlings, 15 are roses.

(WHOLE) (PART)

What percent of the seedlings are roses?

Let x = ____________________________

KEY: 

whole part 100 %  of is 240 15

= 100 x

SOLVE (show work):

SENTENCE: _____________ percent of the seedlings are roses.

2) An outdoor barbeque grill is advertised at $39 off the regular price of $195.

(PART) (WHOLE)

What percent of the regular price will you save?

Let x = ____________________________

KEY: 

whole part 100 %  of is 195 39

= 100 x

SOLVE (show work):

15

3) Felix Festa has about 700 students (WHOLE) in 7th _{grade. Eight percent of the seventh grade}

students play football. How many students play football?

Let x = ____________________________ (not looking for % this time!)

KEY: 

whole part

100 % 

of is

x

= 100

SOLVE (show work):

SENTENCE: ______________________________________________________________

Bonus: How many students DO NOT play football?

4) Your school newspaper’s budget this year is 160% of last year’s budget, which was $2125.

What is this year’s budget?

Let _______________________________________________

KEY: 

whole part

100 % 

of is

2125 x

=

16

5) In John’s math class, 20% of students earned an A on a test. If there were 30 students in the class, how many got an A?

Let x = ____________________________

KEY: 

whole part

100 % 

of is

SOLVE (show work):

SENTENCE:

Bonus: How many students DID NOT get an A?

HOMEWORK – PERCENT PROPORTION

Define a variable and set-up a proportion for each problem. Write your final answer in a complete sentence.

1) Zoey inflated 24 balloons for decorations at the middle school dance. If Zoey inflated

(PART)

15% of the balloons for the dance, how many balloons are there in total? (WHOLE)

Let x = ____________________________

KEY: 

whole part

100 % 

of is

x

24

= 100 SOLVE (show work):

17

AIM: SWBAT solve word problems using the percent proportion. Define a variable, set-up and solve a proportion.

1) The attendance at the school play on Friday was 95% of the attendance on Saturday night. If 220 people attended on Saturday night, how many people attended on Friday?

(WHOLE) (PART)

Let x = ____________________________

KEY: 

whole part 100 %  of is

SOLVE (show work):

SENTENCE: _________________________________________________________.

NOTES:

When interpreting word problems to set up proportions, use this guide:

BASE (Starting Value) (WHOLE)

Original Price

Regular Price

Amount of Merchandise Sold

Amount of the Service

Original Cost

Part (what you add or subtract) (PART)

Amount of discount/sale

Amount of sales tax

Amount of commission

Amount of gratuity

Amount of mark-up

Percent % (p)

Rate discount

sale

Rate of sales tax

Rate

commission

18

Use the percent proportion to solve each word problem.

Write a let statement & sentence.

1) A pair of boots is regularly priced at $85. They are on sale (discount) for 70% off.

(WHOLE)

Find the *amount of discount AND the *sale price.

*Let x = ____________________________

*Let 85 – x = sales price

KEY: 

whole part

100 % 

of is

85 x

=

SOLVE (show work):

The discount is ________________ .

19 2) Jenny earns a 30% commission on all the items she sells. If she sells $870 worth of items,

(WHOLE)

how much commission will she earn?

(PART)

Let x = ____________________________

KEY: 

whole part 100 %  of is 870 x

= 100

SOLVE (show work):

Jenny will earn $_________________ in commission.

3) A jacket costs $50. The rate of sales tax is 8%. (WHOLE)

*How much sales tax must be paid? *What is the total cost of the jacket? (PART)

*Let x = ____________________________

*Let $50 + x = __________________________________

KEY: 

whole part 100 %  of is

50 = 100

SOLVE (show work):

The tax is $________________.

20 4) Your family goes out to dinner and the bill is $85. (WHOLE) You want to tip your waiter 20% for the excellent service he provided.

*How much tip should you leave? (PART) *What would the final cost be?

*Let x = ____________________________

*Let _________________ = the final cost of the dinner bill

KEY: 

whole part

100 % 

of is

= 100

SOLVE (show work):

The tip is $________________.

The final cost of the dinner bill is $_________________.

**If there are 4 members in your family, and you wanted to split the bill evenly, how much money would you each have to pay?

5) A jacket on sale at $48 is selling for 60% off the regular price. Find the regular price.

(PART) (WHOLE)

Let x = ____________________________

KEY: 

whole part

100 % 

of is

SOLVE (show work):

21

AIM: SWBAT use the percent proportion to answer word problems.

Use the percent proportion to solve each word problem. Write a let statement & sentence.

1) Games Galore buys the latest video games at a wholesale price of $30 (WHOLE). The markup rate at Game’s Galore is 40%. *How much is the mark-up? (PART)

*How much will you pay for a video game?

Let x = ____________________________ Let x + ______= the cost of the video game

KEY: 

whole part 100 %  of is

SOLVE (show work):

The mark-up is $_________________.

SENTENCE:

2) A car salesman earns 17% commission on all sales; if he sold a car and earned $3,327.75 in commission what was the price of the car he sold?

Let x = ____________________________

KEY: 

whole part 100 %  of is x 75 . 3327 =

SOLVE (show work):

22 3) A television regularly sells for $699. There is a 10% discount AND an 8.5% sales tax

AFTER discount, what is the final price of the television?

YOU HAVE TO FIND THREE THINGS: DISCOUNT, TAX, FINAL PRICE *Let x = ____________________________

*Let y = ____________________________

*Let $699 - x + y = Final Price of the television

KEY: 

whole part

100 % 

of is

699 x

= (DISCOUNT) 629.10 y

= ( TAX )

The discount is $________________.

The tax is $_________________.

23 4) Jen’s bill at a restaurant before tax and tip is $22. If tax is 5.25% and she wants to leave 15% of the bill before the tax for a tip, how much will she spend in total?

YOU HAVE TO FIND THREE THINGS: TAX, TIP, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let $22 + _______= ______________________

KEY: 

whole part

100 % 

of is

22 x

= (TAX) 22 y

= ( TIP )

The tax is $________________.

The tip is $_________________.

The final price of the bill is $ ____________________.

24 HOMEWORK – DISCOUNT, SALES TAX, COMMISSION, TIP & MARK UP

Use the percent proportion to solve each word problem. Write a let statement & sentence.

1) A couch regularly sells for $899. There is a 10% discount AND 6.5% sales tax AFTER the discount, what is the final price of the couch?

YOU HAVE TO FIND THREE THINGS: DISCOUNT, TAX, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let $899 - x + y = Final Price of the couch

KEY: 

whole part

100 % 

of is

= (DISCOUNT) 809.10

y

= ( TAX )

The discount is $________________.

The tax is $_________________.

25

AIM: SWBAT use the percent proportion to answer word problems.

Use the percent proportion to solve each word problem. Write a let statement & sentence.

1) A cell phone is on sale for 30% off. If the original price is $342.70, what is the sale price? (hint: remember to subtract the discount to find final sale price)

KEY: 

whole part

100 % 

of is

2) A car salesman earns 18% commission on all sales; if he sold a car and earned $4,300 in commission what was the price of the car he sold?

KEY: 

whole part

100 % 

of is

26 3) The Smiths want to buy a new computer. The regular price is $1,049. The store is

offering a 20% discount and a sales tax of 5.25% is added to the discounted price. What is the total cost?

YOU HAVE TO FIND THREE THINGS: DISCOUNT, TAX, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let __________ = ______________________

KEY: 

whole part

100 % 

of is

DISCOUNT TAX

The discount is $________________.

The tax is $_________________.

27 4) Steven’s bill at a restaurant before tax and tip is $54. If tax is 6.25% and he wants to leave 20% of the bill including the tax for a tip, how much will he spend in total?

YOU HAVE TO FIND THREE THINGS: TAX, TIP, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let ___________ = ______________________

KEY: 

whole part

100 % 

of is

TAX TIP

The tax is $________________.

The tip is $_________________.

28 HOMEWORK – DISCOUNT, SALES TAX, COMMISSION, TIP & MARK UP

Use the percent proportion to solve each word problem. Write a let statement & sentence.

1) A couch regularly sells for $1099. There is a 25% discount AND 7.5% sales tax, what is the final price of the couch?

YOU HAVE TO FIND THREE THINGS: DISCOUNT, TAX, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let $1099 - x + y = Final Price of the couch

KEY: 

whole part

100 % 

of is

DISCOUNT TAX

The discount is $________________.

The tax is $_________________.

29 CHALLENGE:

Multi-Step Word Problems with Tax, Tip, and Discounts

1) Best Buy they have a stereo system that sells for $2200 and is on sale for 15% and sales tax is 7%. What is the final cost?

** There are 4 things we need to find here to get the final answer. What are they?

Step 1: Discount Step 2: Sale Price

Step 3: Amount of Tax Step 4: Final cost

SENTENCE: _________________________________________________________________

2) A T.V regularly sells for $699. There is a 10%discount, and an 8.5% sales tax based on the sale price. What is the final price of the T.V?

Step 1: Discount Step 2: Sale Price

Step 3: Amount of Tax Step 4: Final cost

30 3) If you go out to eat with 3 friends and your meal was $72.50, there is 6.75% sales tax

and you want to tip the waiter 15% after tax. How much should each person pay?

Step 1: Amount of Tax Step 2: Cost of bill with tax

Step 3: Amount of Tip on the cost of bill Step 4: Final cost w/ Tip

Step 5: Price per person (Remember, there are 4 people including you)

31

AIM: SWBAT use the formula for simple interest to find interest, principal, rate, or time.

When money is borrowed, interest is charged for the use of that money over a period of time. When the money is paid back, the principal (amount of money that was borrowed) PLUS the interest is paid back. The amount of interest depends on the interest rate (%), the amount of money borrowed (principal) and the length of time that the money is borrowed.

Interest

– The ($) amount of interest that is owed or earned.

Principal (P)-

The amount of money that was borrow, saved or invested.

Rate (R)

- The percent of interest.

Time (T)

- Time is

always

in

years

.

Interest = Principal  Rate  Time

(I = PRT)

*R = Rate should be changed from % to decimal before multiplying (move decimal point 2 places to the left or divide by 100)*

*T = Time is always in years.

Example #1:

Jean has $560 in her savings account. Her account earns 8% interest annually. How much interest will Jean earn after one year?

P = $560

R = 8% .08 T = 1 year

I = PRT

I = (560)(.08)(1) I = $44.80

If she does not deposit or withdraw any money, how much will be in her account after one year?

*INTEREST GETS ADDED TO THE PRINCIPAL AMOUNT*

32

Using the formula I = PRT, how much interest will be made?

Remember: to change percent % to decimal, __________________ by 100 (or move the decimal point two places to the left)

Remember:

I = PRT

1) $50 at 12% for 20 years

Change % to decimal: 12% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

2) $100 at 2% for 15 years

Change % to decimal: 2% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

3) $1250 at 2.5% for 5 years

Change % to decimal: 2.5% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

4) $2000 at 4% for 3 years

Change % to decimal: 4% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

5) $3200 at 7% for *6 months*

Change % to decimal: 7% = _________

Change months to years: fraction then decimal

12

6

months

I = (_________) (_________) (________)

I = $_______________

6) $650 at 4% for *9 months*

Change % to decimal: 4% = _________

Change months to years: fraction then decimal

12

9

months

I = (_________) (_________) (________)

33

CLASSWORK:

Find the interest AND total amount to the nearest cent.

1)

7.5% interest on $500 for one year

Change % to decimal: 7.5% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

2) 8% interest on $750 for 4 years

Change % to decimal: 8% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

3)

$1425 at 2% for

2

2

1

years

Change % to decimal: 2% = _________ Change time to decimal:

21 = _______ so

2

2

1

= _______

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

4)

$875 at 4.5% for

3

4

1

years

Change % to decimal: 4.5% = _________ Change time to decimal:

4

1 _{= _______}

so

3

1

= _______

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

34

5) Lee has $1050 in a savings account that earns 8.75% interest annually. How

much does he have after 6 years?

Change % to decimal: 8.75% = _________

I = PRT I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

SENTENCE:___________________________________________________

____________________________________________________________

6) Carrie borrows $800 from her aunt at 8% interest per year. If she pays her

back after 8 years, how much does Carrie pay?

Change % to decimal: 8% = _________

I = PRT I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

SENTENCE:

35

HOMEWORK: SIMPLE INTEREST

Find the interest.

I = PRT

1) 10% interest on $1000 for 3 years

Change % to decimal: 10% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

2) $650 at 2% for 5 years

Change % to decimal: 2% = _________

I = PRT

I = (_________) (_________) (________)

I = $________________

3) $1200 at 3% for *6 months*

Change % to decimal: 3% = _________

Change months to years: fraction then decimal

12

6

months

I = (_________) (_________) (________)

I = $________________

4) $2350 at 2.5% for *9 months*

Change % to decimal: 2.5% = _________

Change months to years: fraction then decimal

12

9

months

I = (_________) (_________) (________)

36

AIM: SWBAT use the formula for simple interest to find interest, principal, rate, or time.

When money is borrowed, interest is charged for the use of that money over a period of time. When the money is paid back, the principal (amount of money that was borrowed) PLUS the interest is paid back. The amount of interest depends on the interest rate (%), the amount of money borrowed (principal) and the length of time that the money is borrowed.

Interest

– The ($) amount of interest that is owed or earned.

Principal (P)-

The amount of money that was borrowed, saved or invested.

Rate (R)

- The percent of interest.

Time (T)

- Time is

always

in

years

.

Interest = Principal  Rate  Time

(I = PRT)

*R = Rate should be changed from % to decimal before multiplying (move decimal point 2 places to the left or divide by 100)*

*T = Time is always in years.

Example #2:

Joe borrowed $5000 for 6 months at a 10% interest rate, what would the interest be after 6 months?

P = $5000

R = 10% .10 T = 6 months

12

6 _{months = 6 ÷ 12 = _______ year}

I = PRT

I = (5000)(.10)(.5) I = $250.00

How much money will Joe have to repay after six months?

37

Find the interest AND the total amount.

1) Larry invests $100 in a savings plan. The plan pays 4.5% interest each year. How much money will Larry earn in interest after 3 months? How much money will be in his savings plan after 3 months?

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

SENTENCE:___________________________________________________

____________________________________________________________

2)

I = PRT

I = (_________) (_________) (________)

I = $________________

Total Amount = Principal + Interest

Total Amount = __________ + __________

Total Amount = $_________________

38

Find the missing values.

1)

I = $120

P = $50

R = 10%

T = _____

I = PRT

*substitute the known value

________ = (_______) (_______) (______)

*solve algebraically to find the missing value

120 = (50)(.10)(T)

120 = 5T

5 5

24 = T

T = ________ years

2)

I = $37.50

P = $500

R = _____

T = 1 year

I = PRT

*substitute the known value

________ = (_______) (_______) (______)

*solve algebraically to find the missing value

37.50 = (500)(R)(1)

*

Remember:

change the decimal to a

percent by multiplying by 100*

39

3)

I = $240

P = _________

R = 8%

T = 4 years

I = PRT *substitute the known value

________ = (_______) (_______) (______)

*solve algebraically to find the missing value

P = $_______________

4)

I = _________

P = $800

R = 8%

T = 8 years

I = PRT *substitute the known value

________ = (_______) (_______) (______)

*solve algebraically to find the missing value

I = $_______________

Use the formula to find the missing amounts.

1) Alice’s savings account earned $60 interest in 2 years. The interest rate is 2% per year. How much did Alice have before the interest (what was the principal amount)?

I = PRT

*substitute the values into the formula*

_____________ = (_________) (_________) (________)

Solve for P algebraically: (let statement)

P = $________________

40

2) Tom borrowed $6,836 from a bank at a rate of 12%. He owed the bank

$1,230.48 in interest at the end of the loan. How long did Tom take the loan out

for?

Let x = ___________________________________

I = PRT

*substitute the values into the formula*

_____________ = (_________) (_________) (________)

Solve for T algebraically:

T = ________________ years

SENTENCE: __________________________________________________

3) Troy borrows $250 and pays $13.75 in interest after one year. What was his

interest rate?

I = PRT

*substitute the values into the formula*

_____________ = (_________) (_________) (________)

Solve for R algebraically:

*

Remember:

change the decimal to a percent by multiplying by 100*

R = ________________ %

41 MORE PRACTICE – SIMPLE INTEREST

42

Review for Percent Test

When changing a decimal or fraction to a percent you _______________ by 100. When changing a percent to a decimal or fraction you _______________ by 100.

Fill in the missing information in the table.

Use the formula, I = prt to answer questions 1 and 2. P is the principal amount of money, r is the rate written as a decimal and t is the time written in years.

1) A $20,000 deposit earns 3.6% interest for 3 years. If no money is deposited or withdrawn how much interest will be earned at the end of 3 years?

Sentence: ___________________________________________________________

2) How much money will be in the account at the end of 3 years?

Principal + Interest = Total Amount

Sentence: ___________________________________________________________

Fraction Decimal Percent

62%

5 3

0.45

43

3) Julie borrows $5000 from the bank at 10.5% annual interest. The loan is due in 2 years.

How much will she pay in interest?

Sentence: ___________________________________________________________

4) How much will Julie owe the bank at that time?

Principal + Interest = Total Amount

Sentence: ___________________________________________________________

Use the percent proportion to answer each word problem. Show all work and DO NOT FORGET YOUR LET STATEMENT(S).

5) An employee at Coach works on a 7% rate of commission. If she buys a new bag

for $499 (WHOLE), how much commission (PART) will the employee earn?

KEY: 

whole part

100 % 

of is

Don’t forget:

*Let statement

44

6) A pair of shorts is regularly priced at $49.95. There is a 20% discount and a 5% sales tax. What is the final cost of the shorts?

YOU HAVE TO FIND THREE THINGS: DISCOUNT, TAX, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let _________ = ___________________________

KEY: 

whole part

100 % 

of is

DISCOUNT TAX

The discount is $________________. The tax is $_________________.

Regular Price - ____________ = _________________

(discount) (retail price)

Retail price + __________ = ___________.

(tax) (final price)

45

7) You go out to dinner and the bill before tax and tip is $140. If tax is 8.5% and you want to leave 18% of the bill before the tax for a tip, how much will you spend in total?

YOU HAVE TO FIND THREE THINGS: TAX, TIP, FINAL PRICE

*Let x = ____________________________

*Let y = ____________________________

*Let _______________ = _______________________________

KEY: 

whole part

100 % 

of is

TAX TIP

The tax is $________________.

The tip is $_________________.

46

8) There are 30 students in Mrs. Dinet’s class. If 27 of the students have brown eyes, what

percent of the class has brown eyes?

Hint: Set up proportion KEY: 

whole part

100 % 

of is

Don’t forget:

*Let statement

*Sentence

9) A music store bought a CD set at a cost of $20 (WHOLE). When the store sold the CD set, the percent markup was 40%. Find the amount of markup (PART).

Hint: Set up proportion KEY: 

whole part

100 % 

of is

Don’t forget:

*Let statement

47

10) A pair of jeans is on sale for $39.96 (PART) is selling for 80% of the original price. Find the original price (WHOLE) of the jeans.

Hint: Set up proportion KEY: 

whole part

100 % 

of is

Don’t forget:

*Let statement

*Sentence

11) The student council is helping to set-up for a dance. On Thursday afternoon they were able

to inflate 48% of the 150 balloons (WHOLE) they needed. How many balloons (PART)did they inflate?

Hint: Set up proportion KEY: 

whole part

100 % 

of is

Don’t forget:

*Let statement

48

Match the vocabulary word with its definition.

1. ____ discount A. money a salesperson EARNS based on what they sell

2. ____ gratuity B. extra money PAID on an item

3. ____ mark-up C. money SAVED on an item

4. ____ commission D. money ADDED on to the cost of a service

5. ____ sales tax E. the DIFFERENCE between the selling price and the original cost of an item

6. ____ rate F. percent

7. ____ interest G. I = PRT

8. ____ principal H. always in years

9. ____ time I. the price paid for borrowed or earned money