7th Grade Math

Selected Answers and Solutions R11

Selected Answers and Solutions

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17. 
    
    
    
    • 18 > t
    
    
    • 20 - 19 - 18 - 17 - 16 - 15 - 14 - 13 - 12 - 11 - 10
    
    
    
    


18. 
    
    
    
    • 5 < a
    
    
    • 9 - 8 - 7 - 6 - 5 - 4 - 3 - 2 - 1 01
    
    
    
    


19. n ≤ _^12
    
    
    • 212 - 2 - 121 - 1 - 21 0 12 1 121 2 212
    
    
    
    


20. n + 4 > 13; n > 9 25. n - 8 < 10; n < 18


21. p + 17 ≤ 26; p ≤ 9
    2929 m +^785 ≤ 1,500 Write the inequality.
    
    
    • 785 - 785 Subtract 785 from each side.
      m ≤ 715 Simplify.
      Lalo has 715 minutes remaining.
      31a. 42 + x ≥ 74; x ≥ 32 31b. 74 + y ≥ 110; y ≥ 36
    
    
    
    


22. Sample answer: x + 3 < 25 35. C 37. C


23. 25 x = 18 x + 21; 3 appetizers 41. - 2 43. 7

Pages 252–253 Lesson 4-4C

1. x > 3 3. h ≥ 7 5. y < - 4
   77 _-t 4 <^ -^11 Write the inequality.

• (^4) ( _-t 4 ) > - 4 (-11) Multiply each side by reverse the symbol. -4 and
  t > 44 Simplify.

9. y ≤ - 1
   
   
   • 50 - 4 - 3 - 2 - 1 1 2 3 45
   
   
   
   


10. n ≤ -0.5
    
    
    • 2.5- 2 - 1.5- 1 - 0.5 00.5 1 1.5 22.5
    
    
    
    


11. 4 x > 100; x > 25 15. x ≥ 9 17. 4 < t 19. h > 81


12. y > - 5 23. n < 2 25. t > - 12 27. s < 96


13. x < 4

0 1 2 3 4 5 6 7 8 9 10 11

31. y ≥ 2
    
    
    • 5 - 4 - 3 - 2 - 1 0 1 2 3 45
    
    
    
    


32. t ≤ - 25
    
    
    • 27 - 25 - 23 - 21 - 19
    
    
    
    


33. 0.5x > 15; x > 30

3737 5 n -^7 <^ -^52

Write the inequality. The word times

means multiply; the word decrease

means subtract.

+ 7 + 7 Add 7 to each side.

5 n < - 45 Simplify.

_ 55 n < -^45 _ 5 Divide each side by 5.

n < - 9 Simplify.

39. Sample answer: 7y > 42 and _^12 y > 3
    41. Sample answer: When you are not multiplying
    or dividing by a negative number. 43. G
    45. k > 29 47. x < - 33 49. 4 times

Pages 254–257 Chapter Study Guide and Review

1. true 3. true 5. false; less than 7. false;
   subtract 3 from each side 9. true 11. false; _^32


2. 26 15. 3 17. - 13 19. - 2 21. _^14


3. c - 6 = 18; 24 cookies 25. 4 27. - 9 29. 12


4. 14 w = 98; 7 weeks 33. 1.5 35. 20 37. - 5


5. 6 41. - 1 43. 6 d + 5 = 155; 25 DVDs 45. 1


6. 12 rentals 49. n ≤ - 2 51. g > 3 _ 32 53. p < 18


7. d < - 7 57. 6 x < 18.75; 3 packs

Chapter 5 Proportions and

Similarity

Page 264 Chapter 5 Are You Ready?

1. 152 3. 511 5. ^1517 7. no; ^28 ≠ 148 9. no; ^27 ≠ _^1015

Pages 268–271 Lesson 5-1B

1. 6 mi per gal
   33 5 pounds for $2.49 =^
   _$2.49
   5 lb^

Write the rate

as a fraction.

= $2.49 _5 lb ÷÷^5 5 Divide the

numerator and

the denominator

by 8.

= $0.498_1 lb Simplify.

$0.498 rounds to $0.50. So, the cost is $0.50 per

pound.

5. Music Place 7. 60 mi/h 9. 30 people per class
   1111 45.5 meters in 13 seconds = _45.5 m13 s^
   Write the rate as a fraction.
   = _45.5 13 ÷ ÷ 1313 Divide the numerator and the denominatorby 13.^
   = _3.5 m1 s Simplify.
   3.5 meters per second


6. $0.14/oz 15. about $0.50 per pair 17. Susana;
   1.78 m/s > 1.66 m/s > 1.23 m/s 19a. Soft drink C;
   Soft drinks A and B have about 3 milligrams of
   sodium per ounce, and soft drink C has 6 mg per
   ounce. 19b. Soft drink A; 1.83 g/oz < 1.88 g/oz <
   4.29 g/oz 21. $4.98 23. $130.50 25. Sample
   answer: $1.25 per qt; $2.49 ÷ 2 ≈ $2.50 ÷ 2 or $1.25


7. Sample answer: $0.06 per oz; $1.13 ÷ 20 ≈ $1.20
   ÷ 20 or $0.06
   2929 a. 1 hr, 18 minutes, 27 seconds is (1 +^18 ÷^60 +
   27 ÷ 3600) hr or 1.3075 hr.
   26.2 miles in 1.3075 hours = _26.2 miles1.3075 hr
   Write the rate as a fraction.
   = __1.307526.2 ÷ ÷ 1.30751.3075 Divide the numerator and the denominator by 1.3075.

= _20.04 1 Simplify.

R01_R42_EM_SelAns_895130.indd R11 1/18/10 9:51 AM