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Use the Definition of Percents

In the following exercises, write each percent as a ratio.

In 2014 , the unemployment rate for those with only a high school degree was 6.0% .

6 100

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In 2015 , among the unemployed, 29% were long-term unemployed.

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The unemployment rate for those with Bachelor's degrees was 3.2% in 2014 .

32 1000

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The unemployment rate in Michigan in 2014 was 7.3% .

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In the following exercises, write as

  1. a ratio and
  2. a percent

57 out of 100 nursing candidates received their degree at a community college.

  1. 57 100
  2. 57%

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80 out of 100 firefighters and law enforcement officers were educated at a community college.

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42 out of 100 first-time freshmen students attend a community college.

  1. 42 100
  2. 42%

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71 out of 100 full-time community college faculty have a master's degree.

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Convert Percents to Fractions and Decimals

In the following exercises, convert each percent to a fraction and simplify all fractions.

In the following exercises, convert each percent to a decimal.

In the following exercises, convert each percent to

  1. a simplified fraction and
  2. a decimal

In 2010 , 1.5% of home sales had owner financing. ( Source: Bloomberg Businessweek, 5/23–29/2011)

  1. 3 200
  2. 0.015

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In 2000 , 4.2% of the United States population was of Asian descent. ( Source: www.census.gov)

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According to government data, in 2013 the number of cell phones in India was 70.23% of the population.

  1. 7023 10,000
  2. 0.7023

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According to the U.S. Census Bureau, among Americans age 25 or older who had doctorate degrees in 2014 , 37.1% are women.

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A couple plans to have two children. The probability they will have two girls is 25% .

  1. 1 4
  2. 0.25

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Javier will choose one digit at random from 0 through 9 . The probability he will choose 3 is 10% .

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According to the local weather report, the probability of thunderstorms in New York City on July 15 is 60% .

  1. 3 5
  2. 0.6

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A club sells 50 tickets to a raffle. Osbaldo bought one ticket. The probability he will win the raffle is 2% .

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Convert Decimals and Fractions to Percents

In the following exercises, convert each decimal to a percent.

In the following exercises, convert each fraction to a percent.

In the following exercises, convert each fraction to a percent.

1 4 of washing machines needed repair.

25%

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1 5 of dishwashers needed repair.

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In the following exercises, convert each fraction to a percent.

According to the National Center for Health Statistics, in 2012 , 7 20 of American adults were obese.

35%

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The U.S. Census Bureau estimated that in 2013 , 85% of Americans lived in the same house as they did 1 year before.

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Fraction Decimal Percent
1 2
0.45
18 %
1 3
0.0008
2
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Fraction Decimal Percent
1 4
0.65
22 %
2 3
0.0004
3
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Everyday math

Sales tax Felipa says she has an easy way to estimate the sales tax when she makes a purchase. The sales tax in her city is 9.05% . She knows this is a little less than 10% .

  1. Convert 10% to a fraction.
  2. Use your answer from to estimate the sales tax Felipa would pay on a $95 dress.

  1. 1 10
  2. approximately $9.50

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Savings Ryan has 25% of each paycheck automatically deposited in his savings account.

  1. Write 25% as a fraction.
  2. Use your answer from to find the amount that goes to savings from Ryan's $2,400 paycheck.

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Amelio is shoping for textbooks online. He found three sellers that are offering a book he needs for the same price, including shipping. To decide which seller to buy from he is comparing their customer satisfaction ratings. The ratings are given in the chart.

Seller Rating
A 4/5
B 3.5/4
C 85%

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Write seller C’s rating as a fraction and a decimal.

17 20 ; 0.85

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Write seller B’s rating as a percent and a decimal.

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Write seller A’s rating as a percent and a decimal.

80%; 0.8

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Which seller should Amelio buy from and why?

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Writing exercises

Convert 25% , 50% , 75% , and 100% to fractions. Do you notice a pattern? Explain what the pattern is.

1 4 , 1 2 , 3 4 , 1 .

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Convert 1 10 , 2 10 , 3 10 , 4 10 , 5 10 , 6 10 , 7 10 , 8 10 , and 9 10 to percents. Do you notice a pattern? Explain what the pattern is.

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When the Szetos sold their home, the selling price was 500% of what they had paid for the house 30 years ago. Explain what 500% means in this context.

The Szetos sold their home for five times what they paid 30 years ago.

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According to cnn.com, cell phone use in 2008 was 600% of what it had been in 2001 . Explain what 600% means in this context.

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Self check

After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

.

If most of your checks were:

…confidently. Congratulations! You have achieved the objectives in this section. Reflect on the study skills you used so that you can continue to use them. What did you do to become confident of your ability to do these things? Be specific.

…with some help. This must be addressed quickly because topics you do not master become potholes in your road to success. In math, every topic builds upon previous work. It is important to make sure you have a strong foundation before you move on. Who can you ask for help? Your fellow classmates and instructor are good resources. Is there a place on campus where math tutors are available? Can your study skills be improved?

…no—I don’t get it! This is a warning sign and you must not ignore it. You should get help right away or you will quickly be overwhelmed. See your instructor as soon as you can to discuss your situation. Together you can come up with a plan to get you the help you need.

Practice Key Terms 1

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Source:  OpenStax, Prealgebra. OpenStax CNX. Jul 15, 2016 Download for free at http://legacy.cnx.org/content/col11756/1.9
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