Holt CA Course 1

6-5 Solving Percents Problems

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Holt CA Course 1

6-5 Solving Percents Problems

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1. 4x = 90

2. 8x = 96

3. 12x = 180

4. 26x = 182

22.5

12

15

7

Holt CA Course 1

6-5 Solving Percents Problems

Number Sense (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 1

6-5 Solving Percents Problems

Objective:Objective: You will learn You will learn how to solve problems how to solve problems involving percents.involving percents.

Holt CA Course 1

6-5 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 1

6-5 Solving Percents Problems

Proportion Proportion MethodMethodn

100 =16.5

24PartWhole

PartWhole

n • 24 = 100 • 16.5

24n = 1,650

n = 68.75

Sloths spend about 69% of the day sleeping!

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

Holt CA Course 1

6-5 Solving Percents Problems

Solve.

Example 1: Using Proportions to Solve Problems with Percents

A. What percent of 40 is 25?

SMART Response QuestionTo set the properties right click and selectSMART Response Question Object->Properties...

Holt CA Course 1

6-5 Solving Percents Problems

Solve.

Example 2: Using Proportions to Solve Problems with Percents

B. 15 is 25% of what number?

SMART Response QuestionTo set the properties right click and selectSMART Response Question Object->Properties...

Holt CA Course 1

6-5 Solving Percents Problems

Solve.Check It Out! Example 3

A. What percent of 50 is 10?

SMART Response QuestionTo set the properties right click and selectSMART Response Question Object->Properties...

Holt CA Course 1

6-5 Solving Percents Problems

Solve.Check It Out! Example 4

B. 8 is 40% of what number?

SMART Response QuestionTo set the properties right click and selectSMART Response Question Object->Properties...

Holt CA Course 1

6-5 Solving Percents Problems

Helpful Hint

•The sales tax rate is the percent used to calculate sales tax.•Sales tax is an amount you pay in in additionaddition to the price of the item.

Holt CA Course 1

6-5 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?

Example 5: Finding Sales Tax

Restate the question: What percent of $225 is $18?

Holt CA Course 1

6-5 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 6

Restate the question: What percent of $800 is $56?

Holt CA Course 1

6-5 Solving Percents Problems

Joshua buys a sweater that has a sale price of $48. Joshua gives the sales clerk $60 and receives $7.80 in change. What is the sales tax rate?

Check It Out! Example 7

Holt CA Course 1

6-5 Solving Percents Problems

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Holt CA Course 1

6-5 Solving Percents Problems

What percent of 24 is 16.5?

n • 24 = 16.5

n = 0.6875

n = 68.75%

Sloths spend about 69% of the day sleeping!

Equation Equation MethodMethod

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

24 24

Holt CA Course 1

6-5 Solving Percents Problems

Solve.

Example 6: Using Equations to Solve Problems with Percents

A. 35 is 28% of what number?

35 = 28% • n

35 = 0.28 • n

350.28

= 0.28 • n0.28

125 = n

35 is 28% of 125.

Write an equation.Write an equation.

Write 28% Write 28% as a as a decimal.decimal.Divide each Divide each side by side by 0.28.0.28.

Holt CA Course 1

6-5 Solving Percents Problems

Solve.

Example 7: Using Equations to Solve Problems with Percents

B. What percent of 9 is 18?

n • 9 = 18

189

=n • 99

n = 2

n = 2. = 200. = 200%

18 is 200% of 9.

Write an equation.Write an equation.

Divide Divide each side each side by 9.by 9.Write the Write the decimal as a decimal as a percent.percent.

Holt CA Course 1

6-5 Solving Percents Problems

Solve.

Check It Out! Example 8

A. 36 is 24% of what number?

36 = 24% • n

36 = 0.24 • n

150 = n

36 is 24% of 150.

Write an equation.Write an equation.

Write 24% Write 24% as a as a decimal.decimal.Divide each Divide each side by 0.24.side by 0.24.

360.24

= 0.24 • n0.24

Holt CA Course 1

6-5 Solving Percents Problems

Solve.Check It Out! Example 9

B. What percent of 6 is 36?

n • 6 = 36

366

=n • 66

n = 6

n = 600%

36 is 600% of 6.

Write an equation.Write an equation.

Divide Divide each side each side by 6.by 6.Write the Write the decimal as a decimal as a percent.percent.n = 6. = 600. = 600%

Holt CA Course 1

6-5 Solving Percents Problems

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Holt CA Course 1

6-5 Solving Percents Problems

Lesson QuizSolve.

1. 21 is 42% of what number?

2. What percent of 292 is 73?

3. 112% 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%

50

75

1%

6%