1. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Warm Up Warm Up California Standards California Standards Lesson Presentation Lesson PresentationPreview

2. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Warm Up 1. 14,000 is 2 % of what number? 2. 39 is 13% of what number? 3. 37 % of what number is 12? 4. 150% of what number is 189? 560,000 300 32 1 2 126 1 2

3. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease NS1.6 Calculate the percentage of increase and decrease of a quantity. NS1.7 Solve problems that involve discounts, markups, commissions, and profit and compute simple and compound interest. California Standards

4. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Vocabulary percent of change percent of increase percent of decrease discount markup

5. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Percents can be used to describe a change. Percent of change is the ratio of the amount of change to the original amount. Percent of increase describes how much the original amount increases. Percent of decrease describes how much the original amount decreases. amount of change original amount percent of change =

6. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Find the percent of increase or decrease from 16 to 12. Additional Example 1A: Finding Percent of Increase or Decrease This is a percent of decrease. 16 – 12 = 4First find the amount of change. amount of decrease original amount 4 16 Set up the ratio. Find the decimal form. Write as a percent. = 0.25 = 25% 4 16 From 16 to 12 is a 25% decrease.

7. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Find the percent increase or decrease from 45 to 54. This is a percent of increase. 54 – 45 = 9First find the amount of change. amount of increase original amount 9 45 Set up the ratio. Additional Example 1B: Finding Percent of Increase or Decrease Find the decimal form. Write as a percent. = 0.20 = 20% 9 45 From 45 to 54 is a 20% increase.

8. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Find the percent increase or decrease from 50 to 65. This is a percent of increase. Check It Out! Example 1A 65 – 50 = 15First find the amount of change. amount of increase original amount 15 50 Set up the ratio. Find the decimal form. Write as a percent. = 0.30 = 30% 15 50 From 50 to 65 is a 30% increase.

9. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Find the percent of increase or decrease from 20 to 17. Check It Out! Example 1B This is a percent of decrease. 20 – 17 = 3First find the amount of change. amount of decrease original amount 3 20 Set up the ratio. Find the decimal form. Write as a percent. = 0.15 = 15% 3 20 From 20 to 17 is a 15% decrease.

10. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease When Jim was exercising, his heart rate went from 72 beats per minute to 98 beats per minute. What was the percent increase to the nearest tenth of a percent? Additional Example 2: Health Application 26 72 Set up the ratio. 98 – 72 = 26 First find the amount of change. amount of increase original amount Find the decimal form. Write as a percent.  0.361  36.1% 26 72 From 72 to 98 increases by about 36.1%.

11. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease In 2005, a certain stock was worth $1.25 a share. In 2006, the same stock was worth $0.85 a share. What was the percent decrease? Check It Out! Example 2 1.25 – 0.85 = 0.40 First find the amount of change. amount of decrease original amount 1.25 0.40 Set up the ratio. Find the decimal form. Write as a percent. = 0.32 = 32% 1.25 0.40 The value of the stock decreased by 32%.

12. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Discount is the difference between the regular price and the sale price of an item. You can use percent of decrease to find discounts. Markup is the difference between the wholesale cost and the retail price of an item. You can use percent of increase to find markups.

13. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Sarah bought a DVD player originally priced at $450 that was on sale for 20% off. What was the discounted price? Additional Example 3A: Finding Discount and Markup (450)(0.20) = 90Find 20% of $450. This is the amount of discount. 450 – 90 = 360Subtract $90 from $450. Method 2: Subtract, then multiply. 100% – 20% = 80%Find the percent Sarah pays. Method 1: Multiply, then subtract. (450)(0.80) = 360Find 80% of 450. The discounted price was $360.

14. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Additional Example 3B: Finding Discount and Markup (85)(0.40) = 34Find 40% of $85. This is the amount of markup. 85 + 34 = 119 Add $34 to $85. Method 2: Add, then multiply. 100% + 40% = 140%Find the total percent of the selling price. Method 1: Multiply, then add. (85)(1.40) = 119Find 140% of 85. Mr. Olsen has a computer business in which he sells everything 40% above the wholesale price. If he purchased a printer for $85 wholesale, what will be the retail price? The retail price is $119.

15. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Check It Out! Example 3A (750)(0.10)= 75Find 10% of $750. This is the amount of discount. 750 – 75 = 675Subtract $75 from $750. Method 2: Subtract, then multiply. 100% – 10% = 90%Find the percent Lily pays. Method 1: Multiply, then subtract. (750)(0.90) = 675Find 90% of 750. Lily bought a dog house originally priced at $750 that was on sale for 10% off. What was the sale price? The sale price was $675.

16. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Check It Out! Example 3B (30)(0.50)= 15Find 50% of $30. This is the amount of markup. 30 + 15 = 45 Add $15 to $30. Method 2: Add, then multiply. 100% + 50% = 150%Find the total percent of the selling price. Method 1: Multiply, then add. (30)(1.50) = 45Find 150% of 30. Barb has a grocery store in which she sells everything at 50% above the wholesale price. If she purchased a prime rib for $30 wholesale, what will be the retail price? The retail price is $45.

17. Evaluating Algebraic Expressions 6-5 Applying Percent of Increase and Decrease Lesson Quiz Find each percent increase or decrease to the nearest percent. 1. from 12 to 15 2. from 1625 to 1400 3. from 37 to 125 4. from 1.25 to 0.85 5. A computer game originally sold for $40 but is now on sale for 30% off. What is the sale price of the computer game? 14% decrease 25% increase 238% increase 32% decrease $28