goals: use equations to solve percent problems. use percents to solve real-life problems

0-6 PERCENTS

Goals: Use equations to solve percent problems. Use percents to solve real-life problems.

VOCABULARY

Percent – a ratio that compares a number to 100

PERCENT TO FRACTION

Put it over 100 and reduce!!! Examples:

50%

38%

12%

PERCENT TO DECIMAL

Move the decimal point 2 places to the left!!! Examples:

42%

8%

125%

SOLVING PERCENT PROBLEMS

Translate words into a math equation: “is” means = (equals) “of” means ‧ (multiply) “what” means x (variable)

Solve the equation using multiplication or division.

26% OF WHAT NUMBER IS 130

0.26 ‧ x = 130

26% of what number is 130

0.26x = 130 0.26 0.26

x = 500

EXAMPLES1. What is 30% of 70?

2. 14 is 25% of what number?

3. 27 is what percent of 135?

4. 26 is 40% of what number?

5. 48 is what percent of 160?

6. What is 150% of 200?

21

56

20%

65

30%

300

PRACTICE

Worksheet – “0-6 Percents”

WORD PROBLEM #1

There are about 170,000 species of butterflies and moths worldwide. Butterflies and moths make up about 17% of all insect species. Estimate the number of insect species.

17% of something = 170,0000.17x = 170,000

x = 1,000,000 insect species

WORD PROBLEM #2

You read in a magazine that an affordable rent is one that is no more than 30% of your salary. The apartment you want to rent is $625 per month. What must be your salary to afford this apartment?

30% of something = 6250.30x = 625

x = $2083.33

WORD PROBLEM #3

School 25.9%

Sleep-ing

31.6%

Eating,Dress-

ing 14.9%

TV 9.5%

Homework 7.9%

Other 10.2%

The graph shows the amount of time a teenager spends on different activities in a 24 hour period.a. How much time

is spent sleeping?

b. How much time is spent watching TV?

c. How much time is spent doing homework?

7.584 hours

2.28 hours

1.896 hours

WORD PROBLEM #4

Spring 38 people

Summer 52 people

Fall32 people

Winter28

people

150 people were asked to identify their favorite season. The results are shown in the graph below.a. What percent

of people said Fall?

b. What percent of people said Summer?

c. What percent of people said Spring?

21.3%

34.7%

25.3%

HOMEWORK

Pages P21-P22 #10-22 even #24-28 all