7th Grade Math

Selected Answers and Solutions R17

Selected Answers and Solutions

For Homework Help, go to Hotmath.com

Next, subtract the discount from the regular price.

$7.50 - $1.50 = $6.00

5.75% of $6.00 = 0.0575 · 6.00 Apply the tax.

= $0.35 Write 5.75% as a decimal.

Add the tax to the sale price.

$6.00 + $0.35 = $6.35

The cost of the ticket, including tax, is $6.35.

13. $64.80 15. $7.50 17. $180.00
    1919 a. Camera
    Model

Regular

Price ($) Discount

Sale

Price

A 97.99 15% $83.30

B 102.50 20% $82.00

C 75.99 14% $65.35

D 150.50 10% $135.45

b. Sample answer: Subtract the sale price from the

regular price to fi nd the amount of the discount.

Divide the amount of the discount by the

regular price and multiply by 100. Round to

the nearest percent if needed. c. Camera B with

a 20% discount

21. Sample answer: The regular price of a CD is
    $17.95. The total sale price is $13.46 and the total
    cost including tax is $14.23. 23. Sample answer:
    One method is to fi nd 30% of the regular price, and
    then subtract this amount from the regular price.
    Another method is to fi nd 70% of the regular price.
    The second method is more effi cient because after
    mental math is used to fi nd the percent, it can be
    done in one step rather than in two. 25. F


22. about $2 29. -37%, decrease
    Pages 361–362 Lesson 6-3E


23. $38.40 3. $5.80
    55 I = prt^ Formula for simple interest
    I = $4,500 · 0.09 · 3.5 Replace 0.09, and p with $4,500, t with 3.5. r with
    I = $1,417.50
    $1,417.50 interest is paid in 3.5 years.


24. $1,219.00 9. $21.38 11. $123.75 13. $45.31


25. $14.06 17. $1,353.13
    1919 a. I = prt^ Formula for simple interest
    630 = 4,200 · r · 3 Substitute.
    630 = 12,600r Simplify.
    _12,600^630 = 12,600_12,600r Divide each side by 12,600.
    0.05 = r Simplify.
    Write 0.05 as a percent. The interest rate is 5%.
    b. Find the interest earned on $4,200 at a rate of 6%
    over 4 years.
    I = prt Formula for simple interest
    I = 4,200 · 0.06 · 4 Substitute.
    I = $1,008 Multiply.
    Add the interest earned to the principle. Is the total
    at least $5,000?
    $4,200 + $1,008 = $5,208
    Ramon would earn at least $5,000.
    21. $825.60, $852.02, $879.28 23. C 25. $717.40
    27. $8,440 29. $28.75

Pages 366–369 Chapter Study Guide and Review

1. true 3. true 5. false; 100% 7. true 9. false;
   original 11. 39 13. 135 15. 20; _^14 · 80 = 20


2. 30; _^34 · 40 = 30 19. 8; 0.1 · 80 = 8 21. 5%


3. 10.7% 25. $27.49 27. 39 = 0.65 · w; 60 29. 333


4. 93%, increase 33. 10%, increase 35. $13.80


5. $52.12 39. $11.25 41. $47.50 43. $101.25

Chapter 7 Linear Functions

Page 376 Chapter 7 Are You Ready?

1. 22 3. 42 5. 8 7. 14 9. 28 11. 63 13. 30


2. C 17. D 19. B

Pages 380–384 Lesson 7-1B

1. x 3 xy

13 × 1 4

23 × 2 8

33 × 312

43 × 416

Domain: {1, 2, 3, 4};

Range: {3, 6, 9, 12}

3. x 8 xy

18 · 1 8

28 · 216

38 · 324

48 · 432

Domain: {1, 2, 3, 4};

Range: {8, 16, 24, 32}

5. x 2 xy

02 × 00

12 × 12

22 × 24

32 × 36

Domain: {0, 1, 2, 3};

Range: {0, 2, 4, 6}

77 In the rule column, show that you will

multiply 9 times each of the x-values. In the y

column, show each product.

x 9 xy

19 × 1 9

29 × 218

39 × 327

49 × 436

List the x-values as the domain. Domain: {1, 2, 3, 4}

List the y-values as the range. Range: {9, 18, 27, 36}

R01_R42_EM_SelAns_895130.indd R17 1/18/10 9:51 AM