Kinh tế học - Chapter 6: Percents and their applications

Chapter 6Percents and Their ApplicationsConvert decimals to percents (including rounding percents), percents to decimals, and fractions to percentsConvert percents to fractionsPercent and Their Applications#6Learning Unit ObjectivesConversionsLU6.1List and define the key elements of the portion formulaSolve for one unknown of the portion formula when the other two key elements are givenCalculate the rate of percent decreases and increasesPercent and Their Applications#6Learning Unit ObjectivesApplication of Percents -- Portion FormulaLU6.2Table 6.1 - Bag of M&M’s Decimal PercentColor Fraction (hundredth) (hundredth)Yellow 18 .33 32.73% 55Red 10 .18 18.18% 55Blue 9 .16 16.36% 55Orange 7 .13 12.73% 55Brown 6 .11 10.91% 55Green 5 .09 9.09% 55 Total 55 1.00 100.00% 55 = 1Converting Decimals to Percents.6666%8800%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 numberConverting Decimals to Percents.425.42.542.5%Step 1. Move decimal point 2 places to the right. You are multiplying by 100. If necessary add zeros.Rounding Percents.05882355.88%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 %17.0588235Rounding Percents 18 55.327272732.73%32.73727% 55 18.000000 =Step 1Step 2Step 3Converting Percents to Decimals66%.668.244824.4%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.Converting Fractional Percents to Decimals.0025.07757 %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 %43 4Converting Fractions to Percents3475%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%15Converting a Whole Percent (or a Fractional Percent) to a Fraction156%11%8Step 1. Drop the percent symbol. Step 2. Multiply the number by 1/100.Step 3. Reduce to lowest terms 18001415Converting Percents to Decimals12.5%1812 1/2%Step 1. Drop the percent symbol. Step 2. Change the mixed percent to an improper fraction.Step 3. Multiply the number by 1/100Step 4. Reduce to lowest termsNote: If you have a mixed or decimal percent, change the decimal portion to fractional equivalent and continue with Steps 1 to 4.18Solving for PortionSales 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 .80P = $320,000Solving for RateSales 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 BaseR = $320, 000 $400,000R = 80%Solving for BaseSales 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 RateB = $320,000 .80B = $400,000320,000 is 80% of base (1.00 - .20)Calculating Percent Decreases and IncreasesStep 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.Rate of Percent IncreaseRate = Portion Diff . between old and new TV price Base Old TV amountRate = 2.40 oz 16.00 ozRate = .15 or 15% IncreaseSheila 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.Rate of Percent DecreaseRate = Portion Diff . between old and new TV price Base Old TV amountRate = 4 oz. 16.00 ozRate = .25 or 25% DecreaseThe 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?