1. 6-6 Percent of Change Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day Lesson Quizzes Lesson Quizzes

2. 6-6 Percent of Change Warm Up Solve. 1. 10% of what number is 6? 2. What percent of 20 is 8? 3. What is 80% of 60? 4. 50 is what percent of 200? 60 40% 48 25%

3. 6-6 Percent of Change Problem of the Day A pair of $100 sneakers was on sale for 50% off. Then the store manager marked them down another 30%. She then discounted the price by 20%. What is the total discount as a percent of the original price? 72%

4. 6-6 Percent of Change MA.7.A.1.2 Solve percent problems, including problems involving discounts…and percents of increase or decrease. Sunshine State Standards

5. 6-6 Percent of Change Vocabulary percent of change percent of increase percent of decrease

6. 6-6 Percent of Change A percent can be used to describe an amount of change. The percent of change is the amount, stated as a percent, that a number increases or decreases. If the amount goes up, it is a percent of increase. If the amount goes down, it is a percent of decrease. You can find the percent of change by using the following formula. Percent of change = amount of change original amount

7. 6-6 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Additional Example 1A: Finding Percent of Change 65 is decreased to 38. 65 – 38 = 27 percent of change = 27 65  0.4153846 The percent of decrease is about 41.5%. Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round. When a number is decreased, subtract the new amount from the original amount to find the amount of change. Helpful Hint  41.5%

8. 6-6 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Additional Example 1B: Finding Percent of Change 41 is increased to 92. 92 – 41 = 51 Percent of change = 41  1.2439 The percent of increase is about 124.4% Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round.  124.4% 51 When a number is increased, subtract the original amount from the new amount. Helpful Hint

9. 6-6 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Check It Out: Example 1A 70 is decreased to 45. 70 – 45 = 25 percent of change = 25 70  0.3571429 The percent of decrease is about 35.7%.

10. 6-6 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Check It Out: Example 1B 155 is increased to 279. 279 – 155 = 124 Percent of change = 155 = 0.8 The percent of increase is 80%. 124

11. 6-6 Percent of Change The regular price of a bicycle helmet is $42.99. It is on sale for 20% off. What is the sale price? Additional Example 2: Using Percent of Change Step 1: Find the amount of the discount d. 20% · 42.99 = d 0.20 · 42.99 = d 8.598 = d $8.60  d The amount of the discount is $8.60. Think: 20% of $42.99 is what number? Write the percent as a decimal. Multiply. Round to the nearest cent.

12. 6-6 Percent of Change The regular price of a bicycle helmet is $42.99. It is on sale for 20% off. What is the sales price? Additional Example 2 Continued Step 2: Find the sale price. regular price – amount of discount = sales price The sale price is $34.39. $42.99 – $8.60 = $34.39

13. 6-6 Percent of Change The regular price of a computer game is $49.88. It is on sale for 15% off. Check It Out: Example 2 Find the sale price. 0.15 · 49.88 ≈ 7.48 49.88 - 7.48 = 42.40 The sale price is $42.40

14. 6-6 Percent of Change A boutique buys hand-painted T-shirts for $12.60 each and sells them at a 110% increase in price. What is the retail price of the T-shirts? Additional Example 3: Business Application Step 1: Find the actual amount of increase. Think: 110% of $12.60 is what number? 110% · 12.60 = n 1.10 · 12.60 = n 13.86 = n Step 2: Find the selling price. wholesale price + amount of increase = retail price $12.60 + $13.86 = $26.46 The retail price of the hand-painted T-shirts is $26.46 each. Write the percent as a decimal. Multiply.

15. 6-6 Percent of Change Check It Out: Example 3A William makes T-shirts for $7.00 each and sells them after a price increase of 125%. What is the retail price of the T-shirts? 1.25 7.00 = 8.75 p = 7.00 + 8.75 = 15.75 The retail price is $15.75

16. 6-6 Percent of Change Check It Out: Example 3B Last week, Adam observed 50 finches at a bird feeder. This week, he saw an increase of 130% in the number of finches at the bird feeder. How many finches were at the bird feeder this week? 1.30 50 = 65 50 + 65 = 7.00 + 8.75 There were 115 finches at the bird feeder this week.

17. 6-6 Percent of Change Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

18. 6-6 Percent of Change Lesson Quiz Find each percent of change. 1. 10 is increased to 12. 2. 25 is increased to 45. 3. 10 is decreased to 1. 4. The regular price of a coat is $120. It is on sale for 25% off. What is the sale price? 5. A backpack that sells for $42 is on sale for 25% off. Find the sale price. 80% 20% 90% $90 $31.50

19. 6-6 Percent of Change 1.Identify the percent of change. 20 is increased to 22. A. 10% B. 20% C. 30% D. 40% Lesson Quiz for Student Response Systems

20. 6-6 Percent of Change 2.Identify the percent of change. 30 is increased to 54. A. 30% B. 54% C. 75% D. 80% Lesson Quiz for Student Response Systems

21. 6-6 Percent of Change 3.Identify the percent of change. 15 is decreased to 3. A. 80% B. 75% C. 60% D. 50% Lesson Quiz for Student Response Systems

22. 6-6 Percent of Change 4.The regular price of a camera is $140. A store offers 30% off on cameras. At this discounted rate, what is the sale price of a camera? A. $110 B. $105 C. $98 D. $42 Lesson Quiz for Student Response Systems

23. 6-6 Percent of Change 5.A camcorder that sells for $256 is on sale for 30% off. Identify the sale price. A. $195.60 B. $179.20 C. $106.40 D. $76.80 Lesson Quiz for Student Response Systems