2.7 – Percent of Increase and Decrease Goal: I can find percent increase and decrease.

Vocabulary Percent Change A percent change is an increase or decrease given as a percent of the original amount. A percent increase describes an amount that has grown. A percent decrease describes an amount that has been reduced.

Percent Change Percent change = amount of increase or decrease original amount This is expressed as a percentage! So you will have to be careful with decimals!

Find each percent change Find each percent change. Tell whether is a percent increase or decrease. From 25 to 49 Percent change = amount of increase or decrease original amount Percent change = 49 - 25 25 Percent change = 0.96 = 96%. This is a percent increase, why?

Find each percent change Find each percent change. Tell whether is a percent increase or decrease. From 50 to 45 Percent change = amount of increase or decrease original amount Percent change = 50 - 45 50 Percent change = 0.10 = 10%. This is a percent decrease, why?

YOUR TURN: Find each percent change YOUR TURN: Find each percent change. Tell whether is a percent increase or decrease. 1. From 200 to 110 2. From 25 to 30 3. From 80 to 115

Finding the result of a Percent Increase or Decrease Find the result when 30 is increased by 20% 0.20(30) = 6 30 + 6 = 36 Find the result when 65 is decreased by 80% 0.80(65) = 52 65 – 52 = 13

Vocabulary Discount Markup A discount is an amount by which an original priced is reduced. Discount is a % of the original price. Final price = original price – discount. Markup A markup is an amount by which an original priced is increased. Markup is a % of the original price. Final price = original price + markup.

Discounts – two methods Admission to the museum is $8. Students receive a 15% Discount. How much is the discount? How much do students pay? Method 1 – Discount is a percent decrease. 0.15(8) = 1.20 8 – 1.20 = $6.80 Method 2 – Subtract percent discount from 100%. 100% - 15% = 85% 0.85(8) = $6.80 8 – 6.8 = 1.20

Christo used a coupon and paid $7 Christo used a coupon and paid $7.30 for a pizza that normally costs $10.50. Find the percent discount. $10.50 - $7.35 = $3.15 $3.15 = x(10.50) 0.3 = x The discount is 30%

Markups – two methods Caleb buys a necklaces at a wholesale cost of $48 each. He then marks up the price by 75% and sells them. What is the amount of the markup? What is the selling price? Method 1 – Markup is a percent increase. 0.75(48) = 36 48 + 36 = 84 Method 2 – Add the markup to 100%. 100% + 75% = 175% 1.75(48) = 84 84 – 48 = 36

Lars purchased a daily planner for $32. The wholesale cost was $25 Lars purchased a daily planner for $32. The wholesale cost was $25. What was the percent markup? 32 – 5 =27 7 = x(25) 0.28 = x The discount is 28%