Do Now 2/23/12 Take out HW from last night. Take out HW from last night. Exploration Activities 4 & 5 Exploration Activities 4 & 5 Copy HW in your planner. Copy HW in your planner. Text p. 248, #7-20 all, all Text p. 248, #7-20 all, all In your notebook, put the following heading on the top of a new page. Section 6.4 “Percent of Change” In your notebook, put the following heading on the top of a new page. Section 6.4 “Percent of Change”

Objective SWBAT solve problems involving percent of change SWBAT solve problems involving percent of change

If the amount goes up, it is a PERCENT of INCREASE. amount of change amount of change original amount original amount Section 6.4 “Percent of Change” Percent of change Percent of change x 100 the amount that a number increases or decreases written as a percent If the amount goes down, it is a PERCENT of DECREASE. Percent of change =

Find the percent of increase or decrease (round to the nearest tenth of a %). Before: 30 After: 45 Before: 30 After: 45 Before: 115 After: 46 Before: 115 After: 46 Before: 116 After: 146 Before: 116 After: % increase 50% increase 60% decrease 60% decrease 25.9% increase 25.9% increase Amount of change Amount of change Original amount Original amount x 100

From to the enrollment increased by 200, therefore our answer is a percent of increase. actual change actual change original amount ≈ ≈ ≈18.2% increase ≈18.2% increase The enrollment of Howell Middle School South in was 1100 students. In the year the enrollment was 1300 students. What is the percent of increase or decrease between the two years? Percent of increase = : : : – : – 1100 change: 200. change: 200. =

From 1990 to 1991 the number of computers used increased by 0.2 million or 200,000. amount of change amount of change original amount 0.2 million 0.2 million 2 million 2 million =0.1 =0.1 =10% =10%increase There were 2.2 million computers used in public schools in 1991 and 2 million in Find the percent of increase. Percent of increase = 1991: 2.2 million 1991: 2.2 million 1990: million 1990: million change: 0.2 million or 200,000. change: 0.2 million or 200,000.

Shopping and Business Applications ManufacturerPrice SalePrice OriginalPrice RetailPrice Discount Markup

Using a Percent of Change Modell’s buys Nike brand sneakers from the Nike manufacturer for $40. Modell’s then increases the price by 150%. What is the retail price? Retail price = Wholesaleprice + Amount of Increase = 40 + = = $100 What is 150% of 40? or (150% ∙ 40) also known as a “MARKUP”

You buy a shirt that is on sale for 15% off the original price of $25. What is the sale price? =25 – or (15% · 25) = 25 – 3.75 = $21.25 Sale price = Originalprice – Amount of decrease Using a Percent of Change also known as a “DISCOUNT” What is 15% of 25?

Using a Percent of Change Winter Wonders buys snow globes from a manufacturer for $9.20 each sells them at a 95% increase in price. What is the retail price? Retail price = Wholesaleprice + Amount of Increase = = = $17.94 What is 95% of $9.20? or (95% ∙ $9.20) also known as a “MARKUP”

The regular price of an MP3 player is $ This week the MP3 player is on sale 25% off. What is the sale price? =79.99 – or (25% · 79.99) = – = $59.99 Sale price = Originalprice – Amount of decrease Using a Percent of Change also known as a “DISCOUNT” What is 25% of 79.99? $20.00

Using a Percent of Change There were about 198,000 spectators at the NCAA Final Four in The number of spectators increased by about 12% from 1995 to About how many spectators were there in 2002? Spectators in 2002 = Spectators in Amount of increase =198,000+(12% · 198,000) =198,000+23,760 =221,760

Using a Percent of Change In 1983, the average price of CD was $ By 2000, the average price had decreased by 34.8%. What was the average price of a CD in 2000? Price in 2000 = Price in 1983 x Percent of change =$21.50x(100% – 34.8%) =$21.50x65.2% =$ = $14.02

Homework Text p. 248, #7-20 all, all Text p. 248, #7-20 all, all 24