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Transcript of Chapter 06 Percents and Their Applications McGraw-Hill/Irwin Copyright © 2011 by the McGraw-Hill...
Chapter 06
Percents and Their Percents and Their ApplicationsApplications
McGraw-Hill/Irwin Copyright © 2011 by the McGraw-Hill Companies, Inc. All rights reserved.
6-2
1. Convert decimals to percents (including rounding percents), percents to decimals, and fractions to percents
2. Convert percents to fractions
Percent and Their Applications#6#6Learning Unit ObjectivesConversionsLU6.1LU6.1
6-3
1. List and define the key elements of the portion formula
2. Solve for one unknown of the portion formula when the other two key elements are given
3. Calculate the rate of percent decreases and increases
Percent and Their Applications#6#6Learning Unit ObjectivesApplication of Percents -- Portion FormulaLU6.2LU6.2
6-4
Table 6.1 - Bag of M&M’s
Decimal PercentColor Fraction (hundredth) (hundredth)
YellowYellow 18 .33 32.73% 55
RedRed 10 .18 18.18% 55
BlueBlue 9 .16 16.36% 55OrangeOrange 7 .13 12.73%
55BrownBrown 6 .11 10.91%
55GreenGreen 5 .09 9.09% 55TotalTotal 55 1.00 100.00% 55 = 1
6-5
Converting Decimals to Percents
.6666%
8 800%
Step 1. Move decimal point 2 places to the right. You are multiplying by 100. If necessary add zeros.
Step 2. Add a percent symbol at the end of the number
6-6
Converting Decimals to Percents
.425
.42.5
42.5%
Step 1. Move decimal point 2 places to the right. You are multiplying by 100. If necessary add zeros.
6-7
Rounding Percents
.0588235
5.88%
Step 1. When you convert from a fraction or decimal, be sure your answer is in percent before rounding.
Step 2. Identify the specific digit. If the digit to the right of the identified digit is 5 or greater, round the identified digit.
Delete digits to the right of the identified digit.
1 %17
.0588235
6-9
Converting Percents to Decimals
66%.66 8.244
824.4%
Step 1. Drop the percent symbol.
Step 2. Move decimal point 2 places to the left, You are dividing by 100. If necessary add zeros.
6-10
Converting Percents to Decimals
.4%
.4
.00.4
.004
Drop the percent symbol and move the decimal point 2 places to the left.
6-11
Converting Fractional Percents to Decimals
.0025.0775
7 %
Step 1. Convert a single fraction percent to its decimal equivalent by dividing the numerator by the denominator.
Step 2. If a fractional percent is combined with a whole number ( mixed fractional percent) convert the fractional percent first. Then combine the whole number and the fractional percent.
Step 3. Drop the percent symbol; move the decimal point two places to the left (this divides the number by 100).
1 %4
3 4
6-12
Converting Fractional Percents to Decimals
1 %5
.20%
.00.20
.0020
5 1.00 =
Step 1
Step 2
Step 3
6-13
Converting Fractions to Percents
34 75%
Step 1. Divide the numerator by the denominator to convert the fraction to a decimal.
Step 2. Move decimal point 2 places to the right; add the percent symbol.
20%15
6-15
Converting a Whole Percent (or a Fractional Percent) to a Fraction
156%1
1%8
Step 1. Drop the percent symbol.
Step 2. Multiply the number by 1/100.
Step 3. Reduce to lowest terms
1800
1415
6-16
Converting a Whole Percent (or a Fractional Percent) to a Fraction
76%
76 x 1 100
76100
19 25
Reduce
to lowest
term
s
Step 1
Step 2
Step 3
6-17
Converting Percents to Decimals
12.5%
18
12 1/2%
Step 1. Drop the percent symbol.
Step 2. Change the mixed percent to an improper fraction.
Step 3. Multiply the number by 1/100
Step 4. Reduce to lowest terms
Note: If you have a mixed or decimal percent, change the decimal portion to fractional equivalent and continue with Steps 1 to 4.
18
6-18
Converting a Mixed or Decimal Percent to a Fraction
22.5% 45 x 1 = 45 2 100 200
1 2
9 40
Reduce to lowest term
s
22
Step 1 Step 2
Step 3
6-19
Application of Percents - Portion Formula
Portion (P) = Base (B) x Rate (R)
Portion “is”
Base “of” Rate “%”
Base: 100% - whole. Usually given after theword of – but not always $100 – Bonus check
Rate: Usually expressed as a percent but couldalso be a decimal or fraction. 20% taxes
Portion: A number – not a percent and not thewhole $20 taxes
Assume you received a small bonus check of $100 and your company did not withhold any taxes. Compute taxes assuming a 20% in tax rate.
6-20
Solving for Portion
Sales of Milk Chocolate M&M’s® are 80% of total M&M’s® sales. Total M&M’s® sales are $400,000. What are the sales of Milk Chocolate M&M’s®?
Portion (P)= Base (B) x Rate (R)
P = $400,000 x .80
P = $320,000
6-21
Solving for Rate
Sales of Milk Chocolate M&M’s® are 320,000. Total M&M’s® sales are $400,000. What is the percent of Milk Chocolate M&M’s® sales compared to total M&M’s® sales?
Rate = Portion Base
R = $320, 000 $400,000
R = 80%
6-22
Solving for Base
Sales of Peanut and other M&M’s® chocolate candies are 20% of total M&M’s® sales. Sales of Milk Chocolate M&M’s® sales are $320,000. What are the total sales of all M&M’s®?
Base = Portion Rate
B = $320,000 .80
B = $400,000
320,000 is 80% of base (1.00 - .20)
6-23
Calculating Percent Decreases and Increases
Step 1. Find the difference between amounts (such as advertising costs).
Step 2. Divide step 1 by the original amount (the base): R = P / B. Be sure to express your answer in percent.
6-24
Rate of Percent Increase
Rate = Portion Diff . between old and new TV price
Base Old TV amount
Rate = 2.40 oz 16.00 oz
Rate = .15 or 15% Increase
Sheila Leary went to her local supermarket and bought the bag ofM&M’s® shown in Figure 6.1. The bag gave its weight as 18.40 ounces, which was 15% more than a regular 1-pound bag of M&M’s®. Sheila, who is a careful shopper, wanted to check and see if she was actually getting a 15% increase.
6-25
Rate of Percent Decrease
Rate = Portion Diff . between old and new TV price
Base Old TV amount
Rate = 4 oz. 16.00 oz
Rate = .25 or 25% Decrease
The increase in the price of sugar caused the M&M/Mars company to decrease the weight of each 1-pound bag of M&M’s® to 12 ounces. What is the rate of percent decrease?