Download presentation

Presentation is loading. Please wait.

Published byThomasina Caldwell Modified over 7 years ago

1
7-8 Solving Percents Problems Learn to solve problems involving percents.

2
7-8 Solving Percents Problems Sloths may seem lazy, but their extremely slow movement helps to make them almost invisible to predators. 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.

3
7-8 Solving Percents Problems Proportion Method Equation Method n 100 = 16.5 24 Part Whole Part Whole What percent of 24 is 16.5? n · 24 = 100 · 16.5 24n = 1,650 n = 68.75 n · 24 = 16.5 n = 0.6875 n = 68.75% Sloths spend about 69% of the day sleeping!

4
7-8 Solving Percents Problems Solve. Additional Example 1A: Using Proportions to Solve Problems with Percents What percent of 40 is 25? n 100 = 25 40 n · 40 = 100 · 25 40n = 2,500 40n 40 = 2,500 40 n = 62.5 25 is 62.5% of 40. Write a proportion. Set the cross products equal. Multiply. Divide each side by 40 to isolate the variable.

5
7-8 Solving Percents Problems Solve. Additional Example 1B: Using Proportions to Solve Problems with Percents 15 is 25% of what number? 25 100 = 15 n n · 25 = 100 · 15 25n = 1,500 25n 25 = 1,500 25 n = 60 15 is 25% of 60. Write a proportion. Set the cross products equal. Multiply. Divide each side by 25 to isolate the variable.

6
7-8 Solving Percents Problems Solve. Check It Out: Example 1A What percent of 50 is 10? n 100 = 10 50 n · 50 = 100 · 10 50n = 1,000 50n 50 = 1,000 50 n = 20 10 is 20% of 50. Write a proportion. Set the cross products equal. Multiply. Divide each side by 50 to isolate the variable.

7
7-8 Solving Percents Problems Solve. Check It Out: Example 1B 8 is 40% of what number? 40 100 = 8n8n n · 40 = 100 · 8 40n = 800 40n 40 = 800 40 n = 20 8 is 40% of 20. Write a proportion. Set the cross products equal. Multiply. Divide each side by 40 to isolate the variable.

8
7-8 Solving Percents Problems Solve. Additional Example 2A: Using Equations to Solve Problems with Percents 35 is 28% of what number? 35 = 28% · n 35 = 0.28 · n 35 0.28 = 0.28 · n 0.28 125 = n 35 is 28% of 125. Write an equation. Write 28% as a decimal. Divide each side by 0.28 to isolate the variable.

9
7-8 Solving Percents Problems Solve. Additional Example 2B: Using Equations to Solve Problems with Percents What percent of 9 is 18? 18 = n · 9 18 9 = n · 9 9 2 = n 200% = n 18 is 200% of 9. Write an equation. Divide each side by 9 to isolate the variable. Write the decimal as a percent.

10
7-8 Solving Percents Problems Solve. Check It Out: Example 2A 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 to isolate the variable. 36 0.24 = 0.24 · n 0.24

11
7-8 Solving Percents Problems Solve. Check It Out: Example 2B What percent of 6 is 36? 36 = n · 6 36 6 = n · 6 6 6 = n 600% = n 36 is 600% of 6. Write an equation. Divide each side by 6 to isolate the variable. Write the decimal as a percent.

12
7-8 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 = 18 225 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 = 1800 225n 225 = 1800 225 Divide each side by 225. n = 8

13
7-8 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 = 56 800 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 = 5600 800n 800 = 5600 800 Divide each side by 800. n = 7

Similar presentations

© 2023 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google