Selected Answersfor

Core Connections, Course 3

Lesson 7.1.1

7-7. a: 23% b: Coal and renewable totals 30%; natural gas and nuclear also total 30%; students might see either combination or both.

c: Oil and nuclear total 48%.

7-8. See graph at right.

7-9. a: b: c:

7-10. a: No solution. b: Infinite solutions because the lines coincide.

7-11. a: A trapezoid

b: They are right angles.

c:

Lesson 7.1.2

7-17. a: Answers will vary. b: See graph. Answers will vary.

7-18. a: ii: As latitude increases, temperature drops (or as temperatureincreases, latitude drops).

b: iv: All cars, regardless of weight, go about the same speed.

c: iii: No relationship.

d: i: People with more expensive homes tend to have more expensive cars.

7-19. a: 3 b: 1 c: 2

7-20. a: (10)(17) = 72 + 30 + 48 + 20 = 170 square units b: 54 units

7-21. a: 16 b: 2 c: Undefined d: 0

7-22. a: 18%

b: No. The data is not numerical; she could have made a bar graph.

c: 2925 fiction books

1 Core Connections, Course 3

Ride Bike 12.5%

Walk18.75%

Ride in Car31.25%

Bus37.5%

Price (Thousand $)

Horsepower

Lesson 7.1.3

7-29. a: Negative association: as the number of hours watching TV increases, GPA decreases.

b: Positive association: as age increases the number of gray hairs increase.

c: No association between length of hair and shoe size.

7-30. a: See sample graph at left.

b: Answers around 7 or 8 cm are reasonable.

c: About 30 or 31 cm. If the seed is left on the surface of the dirt (0 cm deep), it is predicted that the plant will grow to about 31 inches.

7-31. a: Median = 731, IQR = 870 – 593 = 277

b: Answers will vary.

c: Answers will vary.

7-32. a: b: c: d: or

7-33. a: x = –3 b:

7-34. In any order: translation, rotation, dilation

Selected Answers 2

Depth of seed in pot (cm)

Height of

plant (cm)

Lesson 7.2.1

7-37. This would be an example of a negative association, because as the speed increases, the time it takes to drive a constant distance decreases.

7-38. Let x represent the price of first painting, , , The most expensive painting sold for $10,000.

7-39. a: Range is 68. Both 39 and 107 appear to be outliers.

b: Median = 70, upper quartile = 79.5, lower quartile = 58.5

7-40. a: or b: meters, meters

7-41. a: and , x represents weeks, y represents total money.

b: They will have the same amount between weeks 15 and 16.

7-42. a: or b: c: or

d: or e: f:

Lesson 7.2.2

7-49. a: Line A because it increases most quickly. b: 5 c: They are equal.

7-50. A, D, C B

7-51. 0. A line that is flat or does not go up.

7-52. a: 30 %

b: Water park (30%) and Amusement Park (29%)

c: Answers will vary.

7-53. Let s = # students, a = # adults, , , 1296 students

7-54.

3 Core Connections, Course 3

Lesson 7.2.3

7-61. slope = 

7-62. a: b: c:

7-63. a: x = 5.5 b: x = 42 c: x = –24 d: x = 2

7-64. , . x represents the number of hours she swims. She will swim for 1.5 hours and play volleyball for 3 hours.

7-65. a: line a: , line b:

b: It would lie between lines a and b, because its y-intercept is at (0, 1).

c: It would travel downward but would have the same y-intercept as the line from part (b).

7-66. a: b: c: d:

Lesson 7.2.4

7-71. a: > b: = c: <

7-72. Graph 1: positive, non-linear association, with one outlier, Graph 2: positive linear association with no outliers.

7-73. The slope of is correct because the line is decreasing and for every four units that the line moves to the right, it also goes down 3 units.

7-74. a: x = 12 b: w = 0 c: x = 1 d: No solution

7-75. a: 0 pounds

b: The graph should show a line with positive slope. Units labeled on the axes should be in pounds (vertical axis) and feet (horizontal axis).

c: pounds

d: 9 feet

7-76. a: 4896 sq. units b: sq. units c: 900 sq. units d: 336 sq. units

Selected Answers 4

Lesson 7.2.5

7-81. a: 6.75 miles b:

7-82. Neither,

7-83. A , B , C , D

7-84. a: b: c: d:

7-85. a: b: c:

7-86. a: Let w represent the width of the lawn, .

b: , the width of the lawn is 40 feet, and the length of the lawn is 85 feet.

c: The area of the lawn is 3,400 square feet.

Lesson 7.3.1

7-91. Answers will vary.

7-92. See graph at right. x: (12, 0) and y: (0, 6)

7-93. See graph at far right. –2.

7-94. yearbooks

7-95. a:  P = 40.3 yds., A = 77 sq. yds. b: P = 60 ft., A = 150 sq. ft.

7-96. See graph at right.

a: They do not intersect, because they are parallel.

b: No solution.

c: No solution. Parallel lines do not intersect.

5 Core Connections, Course 3

3.91.52.4

3.6

7.60.67

4.2

11.183.1

24.8

0–77

–49

y

x

y

x

Lesson 7.3.2

7-102. a: Moderate positive linear association with no outliers.

b: If the y-intercept was drawn at the origin or negative, it does not make sense; a child of zero years should have a little positive height.

7-103. a: A box plot shows center and spread of single-variable numerical data nicely.

b: A scatterplot will show the relationship between age and mpg.

c: See graph at right.

d: Weak negative linear association.

e: y = –0.7x + 36

f: About 31 mpg.

g: A slope of negative –0.7 means that for each additional year old a car is, we expect it to go 0.7 less miles per gallon; y-intercept of 36 means that a new car is predicted to go 36 mpg.

7-104. 75 hops

7-105. a: Liz is saving at a greater rate because her line is increasing faster (is steeper).

b: Liz: or , Jeffrey: . The slope tells you at what rate they each are saving.

7-106. a: x = –2 b: x = 15 c: x = 2 d: No solution

Selected Answers 6

0 1 2 3 4 5 6 7 8 9 1020

25

30

35

40

45

Age of Car (years)

Ave

rage

Mile

s per

Gal

lon

Lesson 7.3.3

7-110. a: Number of Highly Fuel Efficient Trucks Purchased: 834 Regular Trucks Purchased: 79184 Low Fuel Prices: 37321 High Fuel Prices: 42697 Fuel prices

b: There does not appear to be an association; only about 1% of cars are fuel efficient, regardless of whether prices are high or low.

7-111. See table below; the independent variable is the hours of sleep; there is an association; as the number of hours of sleep increases, a higher percent of the students remember all ten items.

Remembered all 10 items?Yes No

Less than 7 hours sleep 3.9% 96.1%7-9 hours sleep 9.2% 90.8%At least 10 hours sleep 20.0% 80.0%

7-112. a: Moderate negative association. b: (100, 140)

7-113. Yes, 1500 wph = 25 words per minute; he can text 125 words in 5 minutes

7-114. a: (–11, 18) b: (16, –21)

7-115.a: b:

c: d: x = 12, y = 16

7 Core Connections, Course 3

Low Fuel Prices High Fuel PricesNumber of Highly Fuel Efficient Trucks Purchased 1.1% 1.0%

Number of Ordinary Cars and Regular Trucks Purchased 98.9% 99.0%

Low Fuel Prices High Fuel PricesNumber of Highly Fuel Efficient Trucks Purchased 392 442

Number of Ordinary Cars and Regular Trucks Purchased 36,929 42,255