Mathematical Applications for the Management, Life, and Social Sciences 11th Edition by Ronald J. Ha

 
75. For  and , find .
​ 
 a. 
 b. 
 c. 
 d. 
 e. 
 
ANSWER:  b
 
76. For  and , find .
​ 
 a. 
 b. 
 c. 
 d. 
 e. 
 
ANSWER:  e
 
77. For , find .
​ 
 a. 1
 b. ​
 c. 
 d. ​
 e. x
 
ANSWER:  d
 
78. A couple seeking to buy a home decides that a monthly payment of $800 fits their budget. Their bank’s interest rate is 7.5%. The amount they can borrow A is a function of the time t in years that it will take to repay the debt. If we denote this function by , then the following table defines the function.
​
tAtA
540,00020103,000
1069,00025113,000
1589,00030120,000
 
Source: Comprehensive Mortgage Payment Tables, Publication No. 492, Financial Publishing Co., Boston
 
Choose the expression in the form  which describes how long they will have to make payments if they need to borrow $103,000.
​ 
 a. 
 b. 
 c. ​
 d. 
 e. ​
 
ANSWER:  e
 
79. When a debt is refinanced, sometimes the term of the loan (that is, the time it takes to repay the debt) is shortened. Suppose the current interest rate is 7%, and the current debt is $100,000. The monthly payment R of the refinanced debt is a function of the term of the loan t in years. If we represent this function by , then the following table defines the function.
​
tRtR
51,980.1215898.83
101,161.0920775.30
121,028.3925706.78
​ 
Source: Comprehensive Mortgage Payment Tables, Publication No. 492, Financial Publishing Co., Boston
 
Choose the correct verbal description of .
​ 
 a. From the table,  the value of is the yearly payment to repay a $100,000 loan in 12 years when the interest rate is 7%.
 b. From the table,   the value of is the monthly payment to repay half of a $100,000 loan in 12 years when the interest rate is 7%.
 c. From the table,   the value of is the weekly payment to repay a $100,000 loan in 12 years when the interest rate is 7%.
 d. From the table,   the value of is the monthly payment to repay a $100,000 loan in 12 years when the interest rate is 7%.
 e. From the table,   the value of is the monthly payment to repay a $100,000 loan in 12 years when the interest rate is 7%.
 
ANSWER:  e
 
80. If t represents the number of hours after 9:30 A.M. on Tuesday, October 5, 2004, then the graph defines the Dow Jones Industrial Average D as a function of time t. If we represent this function by  use the graph to find f(6.5).
​ 

​
Source: Bloomberg Financial Markets, The New York Times, October 6, 2004. Copyright © 2004 The New York Times Co. Reprinted by permission.
​
 a. 10,160
 b. 10,175
 c. 10,190
 d. 10,217
 e. 10,220
 
ANSWER:  b
 
81. The number (in millions) of women in the work force, given as a function f, of the year for selected years from 1920 to 2000, is shown in the figure below. Estimate  and explain its meaning.
​​ 

​
Source: 2004 World Almanac
​
 a. : The number of women in the work force increased by 59,000,000.
 b. : The number of women in the work force decreased by 16,000,000.
 c. : The number of women in the work force did not increase.
 d. : The number of women in the work force increased by 16,000,000.
 e. : The number of women in the work force decreased by 59,000,000
 
ANSWER:  d
 
82. The equation  gives the relation between temperature readings in Celsius and Fahrenheit. If a temperature has reading of –20 Fahrenheit, what is the corresponding reading in Celsius?
​
 a. –28.89 C
 b. ​6.67C
 c. –53.78C
 d. –18.22C
 e. –11.17C
 
ANSWER:  a
 
83. The profit from the production and sale of a product is  where x represents the number of units produced and sold. Give the value of P​(3,000).
​
 a. ​$–148,000