Solution to Odd-Numbered Exercises
1. Terry starts at an elevation of 3000 feet and descends 70 feet per second.
3. 3 miles per hour
5. [latex]d\left(t\right)=100 - 10t[/latex]
7. $45 per training session.
9. The rate of change is 0.1. For every additional minute talked, the monthly charge increases by $0.1 or 10 cents. The initial value is 24. When there are no minutes talked, initially the charge is $24.
11. The slope is –400. This means for every year between 1960 and 1989, the population dropped by 400 per year in the city.
13. c
15. 2,300
17. 64,170
19. [latex]P\left(t\right)=75,000+2500t[/latex]
21. (–30, 0) Thirty years before the start of this model, the town had no citizens. (0, 75,000) Initially, the town had a population of 75,000.
23. Ten years after the model began.
25. [latex]W\left(t\right)=\text{7}.\text{5}t+0.\text{5}[/latex]
27. (–15, 0): The x-intercept is not a plausible set of data for this model because it means the baby weighed 0 pounds 15 months prior to birth. (0, 7.5): The baby weighed 7.5 pounds at birth.
29. At age 5.8 months.
31. [latex]C\left(t\right)=12,025 - 205t[/latex]
33. (58.7, 0): In roughly 59 years, the number of people inflicted with the common cold would be 0. (0, 12,025): Initially there were 12,025 people afflicted by the common cold.
35. 2064
37. [latex]y=-2t+180[/latex]
39. In 2070, the company’s profit will be zero.
41. [latex]y=30t - 300[/latex]
43. (10, 0) In 1990, the profit earned zero profit.
45. Hawaii
47. During the year 1933
49. $105,620
51.
a. 696 people
b. 4 years
c. 174 people per year
d. 305 people
e. [latex]P\left(t\right)=305+174t[/latex]
f. 2219 people
53.
a. [latex]C\left(x\right)=0.15x+10[/latex]
b. The flat monthly fee is $10 and there is an additional $0.15 fee for each additional minute used
c. $113.05
55.
a. [latex]P\left(t\right)=190t+4360[/latex]
b. 6640 moose
57.
a. [latex]R\left(t\right)=16 - 2.1t[/latex]
b. 5.5 billion cubic feet
c. During the year 2017
59. More than 133 minutes
61. More than $42,857.14 worth of jewelry
63. $66,666.67