Chapter Three PERCENTS AND THEIR APPLICATIONS Copyright 2014 by
The McGraw-Hill Companies, Inc. All rights
reserved.McGraw-Hill/Irwin Slide 2 LU 3-1: Conversions 1. Convert
decimals to percents (including rounding percents), percents to
decimals, and fractions to percents. 2. Convert percents to
fractions. LU 3-2: Application of PercentsPortion Formula 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. LEARNING UNIT OBJECTIVES 3-2 Slide 3 TABLE 3.1 - BAG OF
M&MS 3-3 Decimal Percent ColorFraction (hundredth)(hundredth)
Yellow Yellow 18.33 32.73% 55 Red Red 10.18 18.18% 55 Blue Blue
9.16 16.36% 55 Orange Orange 7.13 12.73% 55 Brown Brown 6.11 10.91%
55 Green Green 5.09 9.09% 55 Total Total 55 1.00 100.00% 55 = 1
Slide 4 CONVERTING DECIMALS TO PERCENTS 3-4.66 66 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. Step 1 Step 2Step 1 Step 2 % % Slide 5 ROUNDING
PERCENTS 3-5.3272727 32.73% 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. Step 3. Delete digits to the right of the identified digit.
18 55 32.72727% Slide 6 CONVERTING PERCENTS TO DECIMALS 3-6 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. 66.66 824.4 Slide 7 CONVERTING FRACTIONAL PERCENTS TO
DECIMALS 3-7.0775 Step 1. Convert a single fractional percent to
its decimal equivalent by dividing the numerator by the
denominator. If necessary, round the answer. 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). 7 % 3434.0020 1 % 5 1 / 5 = 31 /
4 =.20 07.75 Slide 8 CONVERTING FRACTIONS TO PERCENTS 3-8 3434 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% 1515 3 / 4 = 1 / 5 =.75.20 Slide
9 CONVERTING A WHOLE PERCENT (OR A FRACTIONAL PERCENT) TO A
FRACTION 3-9 156% 1 Step 1. Drop the percent symbol. Step 2.
Multiply the number by 1/100. Step 3. Reduce to lowest terms. 1 800
14 25 156 156 X 1 /100 = 156 100 = 1 56 100 1818 1%81%8 1 X 8 1
/100 = Slide 10 CONVERTING A MIXED OR DECIMAL PERCENT TO A FRACTION
3-10 12.5% 1818 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 its fractional
equivalent and continue with Steps 1 to 4. 1818 25 2 X 1 100 = 12
1212 % = 25 200 = = 12 1212 % = 25 2 X 1 100 = 25 200 = Slide 11
SOLVE PERCENTS WITH THE PORTION FORMULA When solving problems
involving portion, base, or rate, you must give two of these
elements. Portion (P) = Base (B) x Rate (R) 3-11 Slide 12 SOLVING
FOR PORTION 3-12 Sales of Milk Chocolate M&Ms are 80% of total
M&Ms sales. Total M&Ms sales are $400,000. What are the
sales of Milk Chocolate M&Ms? Base (B) x Rate (R) = Portion (P)
$400,000 x.80 = P P = $320,000 Slide 13 SOLVING FOR RATE 3-13 Sales
of Milk Chocolate M&Ms are $320,000. Total M&Ms sales are
$400,000. What is the percent of Milk Chocolate M&Ms sales
compared to total M&Ms sales? $320, 000 $400,000 R = 80% Rate =
Portion Base Slide 14 SOLVING FOR BASE 3-14 Sales of Peanut and
other M&Ms chocolate candies are 20% of total M&Ms sales.
Sales of Milk Chocolate M&Ms sales are $320,000. What are the
total sales of all M&Ms? Portion Rate $320,000.80 B = $400,000
Base = 320,000 is 80% of base (1.00 --.20) Base = Slide 15
CALCULATING PERCENT INCREASES AND DECREASES 3-15 Step 1. Find the
difference between amounts (such as sales). Step 2. Using the
formula B x R = P, solve for R. Be sure to express your answer in
percent. Slide 16 RATE OF PERCENT INCREASE 3-16 Rate = Portion Base
2.40 oz 16.00 oz Rate =.15 or 15% increase Sheila Leary went to her
local supermarket and bought a bag of M&Ms. The bag gave its
weight as 18.40 ounces, which was 15% more than a regular 1-pound
bag of M&Ms. Sheila, who is a careful shopper, wanted to check
and see if she was actually getting a 15% increase. Rate =
Difference between old and new amount Old amount Slide 17 RATE OF
PERCENT DECREASE 3-17 Rate = Portion Base 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&Ms to 12
ounces. What is the rate of percent decrease? 4 oz 16.00 oz Rate =
Difference between old and new amount Old amount
