Holt CA Course Solving Percents Problems Warm Up Warm Up California Standards California Standards Lesson Presentation Lesson PresentationPreview

Holt CA Course Solving Percents Problems Warm Up Solve. 1. 4x = x = x = x =

Holt CA Course Solving Percents Problems NS1.4 Calculate given percentages of quantities and solve problems involving discounts at sales, interest earned, and tips. Also covered: NS1.3, AF1.1 California Standards

Holt CA Course Solving Percents Problems Sloths sleep an average of 16.5 hours a day. To find out what percent of a 24-hour day 16.5 hours is, you can use a proportion or an equation.

Holt CA Course Solving Percents Problems Proportion Method Equation Method n 100 = Part Whole Part Whole What percent of 24 is 16.5? n · 24 = 100 · n = 1,650 n = n · 24 = 16.5 n = n = 68.75% Sloths spend about 69% of the day sleeping!

Holt CA Course Solving Percents Problems Helpful Hint The sales tax rate is the percent used to calculate sales tax.

Holt CA Course Solving Percents Problems Solve. Additional Example 1: Using Proportions to Solve Problems with Percents A. What percent of 40 is 25? n 100 = n · 40 = 100 · 25 40n = 2,500 40n 40 = 2, n = is 62.5% of 40. Write a proportion. Set the cross products equal. Multiply. Divide each side by 40.

Holt CA Course Solving Percents Problems Solve. Additional Example 1: Using Proportions to Solve Problems with Percents B. 15 is 25% of what number? = 15 n n · 25 = 100 · 15 25n = 1,500 25n 25 = 1, n = is 25% of 60. Write a proportion. Set the cross products equal. Multiply. Divide each side by 25.

Holt CA Course Solving Percents Problems Solve. Additional Example 2: Using Equations to Solve Problems with Percents A. 35 is 28% of what number? 35 = 28% · n 35 = 0.28 · n = 0.28 · n = n 35 is 28% of 125. Write an equation. Write 28% as a decimal. Divide each side by 0.28.

Holt CA Course Solving Percents Problems Solve. Additional Example 2: Using Equations to Solve Problems with Percents B. What percent of 9 is 18? 18 = n · = n · = n 200% = n 18 is 200% of 9. Write an equation. Divide each side by 9. Write the decimal as a percent.

Holt CA Course Solving Percents Problems A portable DVD player costs $225 before tax at an appliance warehouse. What is the sales tax rate if the tax is $18? Additional Example 3: Finding Sales Tax n 100 = n · 225 = 100 · 18 8% of $225 is $18. The sales tax is 8%. Write a proportion. Set the cross products equal. Multiply. Restate the question: What percent of $225 is $18? 225n = n 225 = Divide each side by 225. n = 8

Holt CA Course Solving Percents Problems Solve. Check It Out! Example 1 A. 8 is 40% of what number? = 8n8n n · 40 = 100 · 8 40n = n 40 = n = 20 8 is 40% of 20. Write a proportion. Set the cross products equal. Multiply. Divide each side by 40.

Holt CA Course Solving Percents Problems Solve. Check It Out! Example 2 B. 36 is 24% of what number? 36 = 24% · n 36 = 0.24 · n 150 = n 36 is 24% of 150. Write an equation. Write 24% as a decimal. Divide each side by = 0.24 · n 0.24

Holt CA Course Solving Percents Problems A new flat screen TV costs $800 before tax at an appliance warehouse. What is the sales tax rate if the tax is $56? Check It Out! Example 3 n 100 = n · 800 = 100 · 56 7% of $800 is $56. The sales tax is 7%. Write a proportion. Set the cross products equal. Multiply. Restate the question: What percent of $800 is $56? 800n = n 800 = Divide each side by 800. n = 7

Holt CA Course Solving Percents Problems Lesson Quiz Solve is 42% of what number? 2. What percent of 292 is 73? % of what number is 84? 4. What percent of 1,340 is 13.4? 5. An ad features a bicycle on sale for $139. If the total cost of the bike is $147.34, what is the sales tax rate? 25% % 6%