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

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

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%

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

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

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

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 = 27 percent of change =  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%

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 – 41 = 51 Percent of change = 41  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

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 = 25 percent of change =  The percent of decrease is about 35.7%.

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 – 155 = 124 Percent of change = 155 = 0.8 The percent of increase is 80%. 124

6-6 Percent of Change The regular price of a bicycle helmet is $ 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% · = d 0.20 · = d = 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.

6-6 Percent of Change The regular price of a bicycle helmet is $ 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 $ $42.99 – $8.60 = $34.39

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

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% · = n 1.10 · = n = n Step 2: Find the selling price. wholesale price + amount of increase = retail price $ $13.86 = $26.46 The retail price of the hand-painted T-shirts is $26.46 each. Write the percent as a decimal. Multiply.

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? = 8.75 p = = The retail price is $15.75

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? = = There were 115 finches at the bird feeder this week.

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

6-6 Percent of Change Lesson Quiz Find each percent of change is increased to is increased to is decreased to 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

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

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

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

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

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