8.The population of Alabama in 2007 was about 4,628,000, with 26.5% represented by
African-Americans. What is the best estimate of the African-American population in
Alabama? (Source:U.S. Census Bureau.)
A.600,000 B.750,000 C.1,200,000 D. 1,500,000
9.The graph shows the breakdown, by approxi-
mate percents, of the colors chosen for new
2007 model-year full-size and intermediate
cars sold in the United States. If approxi-
mately 3.8 million of these cars were sold,
about how many were each color? (Source:
Ward’s Communications.)
(a)White (b)Silver (c)Red
10.An average middle-income family
will spend $221,190 to raise a child
born in 2008 from birth to age 18.
The graph shows the breakdown, by
approximate percents, for various
expense categories. To the nearest
dollar, about how much will be
spent to provide the following?
(a)Housing
(b) Food
(c) Health care
Concept Check Answer each question.
11.Suppose that a chemist is mixing two acid solutions, one of 20% concentration and the
other of 30% concentration. Which concentration could notbe obtained?
A.22% B.24% C.28% D. 32%
12.Suppose that pure alcohol is added to a 24% alcohol mixture. Which concentration could
notbe obtained?
A.22% B.26% C.28% D. 30%
Work each mixture problem. See Example 2.
146 CHAPTER 2 Linear Equations and Inequalities in One Variable
Source: DuPont Automotive Products.
White
14%
Brown/Beige
7% Silver
21%
Black
13%
Blue
14%
Gray
12%
Red
13%
Other
6%
Most Popular Automobile Colors
Source: U.S. Department of Agriculture.
Miscellaneous
11%
Child care/
education 12%
Transportation 14%
Health care
8%
Clothing 5%
Housing
33%
Food
17%
The Cost of Parenthood
13.How many liters of 25% acid solution
must a chemist add to 80 L of 40% acid
solution to obtain a solution that is 30%
acid?
14.How many gallons of 50% antifreeze
must be mixed with 80 gal of 20%
antifreeze to obtain a mixture that is
40% antifreeze?
Liters of Liters of
Solution Rate Acid
x 0.25 0.25x
80 0.40 0.40
x+ 80 0.30 0.30 1 x+ 802
1802
Gallons of Gallons of
Mixture Rate Antifreeze
x 0.50 0.50x
80 0.20 0.20
x+ 80 0.40 0.40 1 x+ 802
1802
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