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Percents And Equations

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Chapter 6, Section 6: Percents and Equations

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Percents And Equations

  1. 1. Chapter 6, Section 6: Percents and Equations <ul><li>Warm Up: Write each percent as a decimal </li></ul><ul><li>48% </li></ul><ul><li>5% </li></ul><ul><li>23.8% </li></ul><ul><li>72.25% </li></ul><ul><li>136% </li></ul><ul><li>178.5% </li></ul><ul><li>0.48 </li></ul><ul><li>0.05 </li></ul><ul><li>0.238 </li></ul><ul><li>.7225 </li></ul><ul><li>1.36 </li></ul><ul><li>1.785 </li></ul>
  2. 2. Writing and Solving Percent Equations <ul><li>Solve a Percent problem by writing and solving an equation. </li></ul><ul><li>When you use a percent in an equation, write it as a decimal. </li></ul>
  3. 3. Finding The Percent <ul><li>What Percent Of 40 is 6? </li></ul><ul><li>N • 40 = 6 </li></ul><ul><li>N = 6 /40 </li></ul><ul><li>N = 0.15 </li></ul><ul><li>N = 15% </li></ul>Equation The unknown is the percent TIMES the whole. 6 is the percentage of the whole. OF = Whole IS = Part Multiply the percent (as a decimal) by the whole to get the part .
  4. 4. Finding the Part <ul><li>What is 15% of 40? </li></ul><ul><li>N = 0.15 • 40 </li></ul><ul><li>N = 0.15 • 40 </li></ul><ul><li>N = 6 </li></ul><ul><li>6 is 15% of 40 </li></ul>Equation The unknown is 15% of 40. 6 is the PART of 40 40 is the whole. OF = Whole IS = Part Whole x Percentage = Part
  5. 5. Finding the Whole <ul><li>6 is 15% of what? </li></ul><ul><li>6 = .15 • N </li></ul><ul><li>6/.15 = N </li></ul><ul><li>40 = N </li></ul><ul><li>6 is 15% of 40 </li></ul>Equation The unknown is the whole here. 6 is 15% of a whole that we don’t know. OF = Whole IS = Part Whole x Percentage = Part
  6. 6. What is 85% of 62? <ul><li>1 st : What are we looking for? Percent, Part, or Whole? </li></ul><ul><li>2 nd : Looking for Part: Write an equation, with the Percent as a Decimal. </li></ul><ul><li>N = .85 • 62 </li></ul><ul><li>Simplify: N = 52.7 </li></ul><ul><li>85% of 62 is 52.7 (52.7 = Part of 62) </li></ul>
  7. 7. This Works For Percentages Greater Than 100 As All. <ul><li>What percent of 48 is 54? </li></ul><ul><li>What are we looking for? </li></ul><ul><li>Write an Equation. </li></ul><ul><li>N • 48 = 54 </li></ul><ul><li>Simplify: N = 54/48 = 1.125 </li></ul><ul><li>Move the Decimal point 2 times. </li></ul><ul><li>N = 112.5% </li></ul>
  8. 8. Write an Equation and Solve It <ul><li>What is 45.5% of 20? </li></ul><ul><li>380 is 125% of what number? </li></ul>N = 0.455 • 20, N = 9.1 380 = 1.25 • N , N = 304
  9. 9. Using Equations to Solve Percent Problems <ul><li>Commission : The amount of money a job pays you based on how much you sell. </li></ul><ul><li>REAL LIFE FOLKS! </li></ul>Hint: Commission is the part, so what number is the whole?
  10. 10. Real Estate Game of Life <ul><li>A real estate agent makes a 4.5% commission on property she sells. How much does she make on the sale of a house for $245,000? </li></ul>1 st : Percent, Part or Whole? 2 nd : Write an Equation. 3 rd : Simplify and Solve. Amount of Commission IS 4.5% OF $245,000 C Commission = .045 X $245,000 Commission, C = $11,025.00
  11. 11. Elvis Lives! <ul><li>If Elvis was alive when CDs were invented he would receives 5% of royalty on each CD sale. To the nearest cent, find Elvis’s royalty for each CD that sells for $16.99. </li></ul>The Elvis makes $0.85 off of each CD sale.
  12. 12. Peanut Butter <ul><li>In a survey, 922 people, or about 68.6%, preferred smooth peanut butter to chunky. How many people were surveyed? </li></ul>1,344 people were surveyed. Remember: Part = Whole x Percentage
  13. 13. Assignment #22 <ul><li>Page 313-314: 5-28 all. </li></ul><ul><li>www.phschool.com </li></ul><ul><li>Code: awe-0606 </li></ul>

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