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Mathematical and Technological Literacy I
Assignment 2: Exponential Modeling with Percentages

Please do the following for each individual assignment

Open a new Word document. At the top of the document enter all group members names and last names, and Assignment number.

How to save your file: Always save your work as .doc or .docx format.

Where to save your file: Always save your activity in the Group Files under your Activity Group in D2L. All work must be saved here. Additional options of saving such as email or flash drives are only back up methods and should not be used as primary modes of saving.

How to submit your activity: Once you complete your activity you need to submit it through D2L's Dropbox, under the correct dropbox for your activity. To ensure that you get evaluated and get a grade, make sure you submit before the deadline.

Deadlines are strict, no exceptions. Late submissions are not accepted. Incorrect submissions, submissions which cannot be opened due to wrong file type, or corrupt files will not be graded and will receive a grade of zero. Plagiarism receives a zero as a grade and will  be reported without exception.

 

1. a.  A ticket to the Lovehammers concert at Metro was marked up by 95.5%.  If the original price was $10, what was the final price including fees (the marked up price)?

b.  On August 16, 2005, one share of Telephone & Data Systems Inc. stock cost $42.90.  On September 2, 2005, the stock closed 5% lower than the price on August 16th.  What was the cost of one share of Telephone & Data Systems Inc. stock on September 2nd?

2.  The burning of fossil fuels (oil, coal, natural gas) releases carbon dioxide into the atmosphere.  Carbon dioxide is known as a greenhouse gas because it tends to trap heat in the atmosphere, causing global warming.  In 1995, the United States emitted about 1.4 billion tons of carbon (as carbon dioxide) into the atmosphere. China was second largest contributor, emitting 850 million tons.  US emissions were increasing at 1.3% a year, while Chinese emissions were increasing at 4% a year. Assuming these growth rates continued determine the year when China will exceed US in carbon emissions.

3.  In order to understand the prehistory of the Hawaiian island of Lana'i better, anthropologists Maria Sweeney, Melinda Allen, and  Boyd Dixon used radiocarbon dating on charcoal found in an ancient dwelling site, the Kaunolu Village National Historic Landmark, the largest archeological complex on the island.  In one of their samples, they found that approximately 94% of the original carbon 14 remained.  Using the fact that Carbon 14 decays by 1.202% every 100 years, determine the approximate age of the this sample .  In your word document, paste the Excel table you made to come up with your answer.

Lana'i.jpg (21996 bytes)
Hulopoe Beach on Lana'i

Copyright 1998 B. David Cathell, Phoenix, AZ

 

Relative/Percentage Change

                        Relative Change =  =

For communication purposes, we convert relative change, which is a fraction (converted to a decimal number) to a percentage (percentage change).  The following are three ways to convert a fraction (decimal number) to a percentage: 

 For this course, we will generally show percentages formatted to two (2) decimal places (unless stated otherwise).

4.  Chicken Bacteria:  The information given below was found on the label of a package of Chicken.

Bacteria Count on Chicken
(per square centimeter when refrigerated at 40º F)

Day Bacteria Condition
0 360 OK
1 5,760 OK
2 92,160 Fair
3 1,474,560 Poor
4 23,592,960 Odor
5 377,487,360 Slime

 

a.  By using the percentage change formula above, show that the above data is exponential.  What is the percentage increase in bacteria each day?

b.  It is also noted on the label that at 40º F, the bacteria double in number every 6 hours.  Make a new table showing the bacteria count every 6 hours.  To get you started, you table should look like this:

Hour Bacteria
0 360
6  
12  
18  
24  
30  

You should continue your hours column to 120 hours.  Paste your Excel table in your word document.

c.  What is the percentage increase in bacteria every six hours?

5. In 1980, the number of African elephants was 1,200,000 but that number was decreasing 5.25% a year. 

a. How many African elephants were there in 1988?  Show either your table or your calculation.

b. How many years did it take for the population to reach 1/2 of what it was originally?   Show your table.

6.  In 2010, the 2009 populations and projected population rates were released for Russia and Ethiopia.  The population of Russia in 2009 was 140.9 million; the population of Ethiopia was 82.8 million.  Russia is decreasing in population by approximately 0.4% annually; the population of Ethiopia is growing at 2.6%. Using Excel, answer the following questions. 

a.  How long, at the above rates, will it take for the population of Ethiopia to double? 

b.  How long, at the above rates, will it take for the population of Russia to reach 125 million?