Over Lesson 7–5 A.A B.B C.C D.D 5-Minute Check 6 A.9.4% B.1.06% C.5.7% D.6% Taneesha bought a laptop for $ including tax. The laptop had a price of $ What percent sales tax did she pay?

Splash Screen

Then/Now You have already solved real-world problems using the percent proportion. (Lesson 7–3) Find percent of increase and decrease. Solve real-world problems involving markup and discount.

Vocabulary percent of change percent of increase percent of decrease markup selling price discount The ratio of the increase or decrease of an amount to the original amount The ratio of an amount of increase to the original amount, expressed as a percent The ratio of an amount of decrease to the original amount, expressed as a percent (negative value) The amount the price of an item is increased above the price of the store paid for an item The amount a customer pays for an item The amount by which the regular price of an item is reduced

Concept

Example 1 Find the Percent of Change Find the percent of change from 20 students to 24 students. State whether the percent of change is an increase or decrease. Step 1Subtract to find the amount of change. 24 – 20 = 4final amount – original amount Step 2Write a ratio that compares the amount of change to the original amount. Express the ratio as a percent.

Example 1 Find the Percent of Change Simplify. Answer: 20%; increase Step 3The decimal 0.20 is written as 20%. The percent of change is positive, so it is a percent of increase.

A.A B.B C.C D.D Example 1 A.–20%; decrease B.–25%; decrease C.20%; increase D.25%; increase What is the percent of change from 24 to 30 students?

Example 2 Find the Percent of Change Pedro had 325 trading cards. He now has 270 trading cards. Find the percent of change. Round to the nearest tenth, if necessary. Then state whether the percent of change is an increase or decrease. Step 1Subtract to find the amount of change. 270 – 325 = –55final amount – original amount Step 2Write a ratio that compares the amount of change to the original amount. Express the ratio as a percent.

Example 2 Find the Percent of Change Divide. Use a calculator. Answer: To the nearest percent, the percent of change is –16.9%. Because the percent is negative, it is a percent of decrease. Substitution

A.A B.B C.C D.D Example 2 A.–17.9%; decrease B.–21.7%; decrease C.17.9%; increase D.21.7%; increase John had $420 in his checking account at the beginning of May. At the beginning of June he had $345. What was the percent of increase or decrease to the nearest tenth?

Example 3 Find the Selling Price Find the selling price if a store pays $68 for a portable DVD player, and the markup is 35%. Method 1Find the amount of markup first. The whole is $68. The percent is 35. You need to find the amount of the markup, or the part. Let m represent the amount of the markup. So, $68 + $23.80 = $ Cross Products m = $23.80

Example 3 Find the Selling Price Method 2Find the total percent first. Answer: Using either method, the selling price is $91.80 Since we pay an additional 35%, it is like the price of the item is at 135% of the price the store paid m = $91.80

A.A B.B C.C D.D Example 3 A.$28.80 B.$48.40 C.$67.20 D.$88.00 The markup on a pair of shoes is 40%. If the store paid $48 for a pair of shoes, what is the selling price?

Example 4 Find the Sale Price BASEBALL MITT CR Sporting Goods is having a sale. A baseball mitt has an original price of $89. It is on sale for 25% off the original price. Find the sale price of the baseball mitt. Method 1Find the amount of the discount. The whole is $89. The percent is 25. You need to find the amount of the discount, or the part. Let d represent the amount of the discount. d = $ So, $89 – $22.25 = $66.75.

Example 4 Find the Sale Price Method 2Find the total percent first. Answer: Using either method, the sale price is $ We use 75% because we are taking away 25% from the original price (100%) d = $66.75

A.A B.B C.C D.D Example 4 A.$11.20 B.$20.80 C.$27.00 D.$43.20 A store is having a 35% off sale. What is the sale price of a shirt normally costing $32?

End of the Lesson