Example: 10 is 50% of 20. amount % base. = times. Amount = % Base

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1 7.2 Solving Percent Problems Example: 10 is 50% of 20 times Amount % Base ** Note: Must change % to decimal before multiplying. Drop the % sign and move the decimal point two places to the LEFT. If there is no decimal place, just start at the % sign % What good is it to show 1010? I already know that! How about this question (Example 5 p.456): What number is 160% of 15.8? Usually,the number before the word, is is the and the number after the word of is the base. In this case we are asking for the. Amount 160% Why is the Amount bigger than the base?

2 Example 2 p is what percent of 32? Percent Amount Base This equation gives you the percent as a decimal value, though, so you must then convert it to a percent by moving the decimal place to the RIGHT two places and then putting a % sign at the end. Percent %

3 Base Amount Percent Example 3 p is 33? % of what number? How do you write 33? as a decimal? We can t write it as. 33? This is a special percent. To convert it we first have to change it to a fraction with denominator % If you get a repeating decimal when converting a decimal, it s better to leave it as a fraction. Base Amount Percent

4 Example 8 p. 458 Circle Graphs (or Pie Charts) A circle graph (aka Pie Chart) is a specialized graph used in statistics in which the relative proportions of parts of a whole (usually given as percentages) are shown as different size wedges of a pie. All the wedges of the pie add up to 100% Presidential Election John Kerry 38% Preident Bush 62% According to the pie chart above, find the number of states won by George W. Bush in the 2004 Presidential Elections. What are we being asked to find? Given: Percentage of votes of each candidate. What is the base? What is the? You do p. 460 #13 Types of Messages Other 4% Work or School 5% Request e- commerce 16% Spam? Family and Friends 31%

5 7.3 Application of Percent Example 1 Find the sales tax on a purchase of $56.35 if the sales tax rate is 5%. Sales Tax Sales Tax Rate Purchase Price (Amount) (Percent) (Base) Sales Tax Rate must be converted to decimal form before multiplying. 5% Sales Tax What is the Total Price? Total Price Purchase Price + Sales Tax Example 2 A waitress found that $11.04 was deducted from her weekly gross earning of $240 for federal income tax. What withholding tax rate was used? What are we being asked to find? What is given?

6 Commission Commission Commission Rate Purchase Price Since Commission is a money, you will need to round your answer to the nearest cent (hundredth). Example 3 Find the commission from the sale of a refrigerator costing $ if the commission rate for a sales person is 16.5% Commission $ Discount Discount Discount Rate Original Price Sale Price Original Price Discount Example 6 Find the of the discount on a pair of shoes advertised at 25% off whose regular price is $ Then find the sale price. Discount 25% $ $59.80 $14.95 Sale Price $ $14.95 $44.85 From these formulas you can find any of those items if the other items are given: Discount Rate Discount /Original Price Orignal Price Discount/Discount Rate Original Price Sale Price + Discount Discount Original Price Sale Price

7 Percent Increase (or Decrease) Percent Increase (or Decrease) Larger Amount - Smaller Amount Original Amount This gives you the answer in decimal form, however, so you have to convert it to percent form. Example 4 A 1996 auction included an oak rocking chair used by President John F. Kennedy in the Oval Office. The chair, originally valued at $5,000, sold for $453,500. Find the percent of increase in the value of the rocking chair. Percent Increase (or Decrease) $453,500 - $5,000 $5,000 $448,500 $5,000 Larger Amount - Smaller Amount Original Amount 89.7 Remember, when converting from decimal from to percent form, you move the decimal point to the RIGHT two places and insert a % sign at the end. Insert zeros if the are no digits where you move the decimal point %