Intermediate Algebra (11th edition)

(Marvins-Underground-K-12) #1

The Blood Alcohol Concentration (BAC) of a person who has been drinking is given by the
expression


number of oz % alcohol body weight in lb hr of drinking.

(Source:Lawlor, J., Auto Math Handbook: Mathematical Calculations, Theory, and Formulas
for Automotive Enthusiasts,HP Books.)


98.Suppose a policeman stops a 190-lb man who, in 2 hr, has ingested four 12-oz beers
(48 oz), each having a 3.2% alcohol content.
(a)Substitute the values into the formula, and write the expression for the man’s BAC.
(b)Calculate the man’s BAC to the nearest thousandth. Follow the order of operations.
99.Find the BAC to the nearest thousandth for a 135-lb woman who, in 3 hr, has drunk three
12-oz beers (36 oz), each having a 4.0% alcohol content.


  1. (a)Calculate the BACs in Exercises 98 and 99if each person weighs 25 lb more and the
    rest of the variables stay the same. How does increased weight affect a person’s BAC?
    (b)Predict how decreased weight would affect the BAC of each person in Exercises 98
    and 99.Calculate the BACs if each person weighs 25 lb less and the rest of the
    variables stay the same.


101.An approximation of the amount in billions of dollars that
Americans have spent on their pets from 1996 to 2008
can be obtained by substituting a given year for xin the
expression


(Source:American Pet Products Manufacturers Associa-
tion.) Approximate the amount spent in each year. Round
answers to the nearest tenth.
(a) 1996 (b) 2002 (c) 2008
(d)How has the amount Americans have spent on their
pets changed from 1996 to 2008?

102.An approximation of the average price of a theater ticket in
the United States from 1977 through 2007 can be obtained
by using the expression.


where xrepresents the year. (Source:National Association
of Theater Owners.)
(a)Use the expression to complete the table. Round answers to the nearest cent.
(b)How has the average price of a theater ticket in the United States changed from 1977
to 2007?

0.1399x-274.4,

1.909x-3791.

0.075, - *0.015


SECTION 1.3 Exponents, Roots, and Order of Operations 31


Average Price
Year (in dollars)
1977
1987 3.58
1997
2007

Solve each problem.


Residents of Linn County, Iowa, in the Cedar
Rapids Community School District can use the
expression


to determine their property taxes, where v is
assessed home value. (Source: The Gazette.)
Use the expression to calculate the amount of
property taxes to the nearest dollar that the
owner of a home with each of the following val-
ues would pay. Follow the order of operations.


95.$100,000 96.$150,000 97.$200,000

1 v*0.5485- 48502 , 1000 *31.44
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