7th Grade Math

INSTANT MESSAGING Use the information at the left to predict

how many of the 2,450 students at Washington Middle School

use emoticons on their instant messengers.

You need to predict how many of the 2,450 students use emoticons.

Words

Variable

Equation

What number of students is 85% of 2,450 students?

Let n represent the number of students.

n = 0.85 · 2,450

n = 0.85 · 2,450 Write the percent equation.

n = 2,082.5 Multiply.

About 2,083 of the students use emoticons.

b. INSTANT MESSAGING This same survey found that 59% of people

use sound on their instant messengers. Predict how many of the

2,450 students use sound on their instant messengers.

Example 1^11 SPENDING Use the circle graph that shows

Save it

33%

Clothing/

jewelry

21%

Other

9%

Go to

movie

5%

Music CD

32%

How Would You

the results of a poll to which 60,000 teens Spend a Gift of $20?

responded.

a. How many of the teens surveyed said

that they would save their money?

b. Predict how many of the

approximately 28 million teens

in the United States would buy a

music CD if they were given $20.

Example 2 2. FOOD Use the bar graph that shows Favorite Ice Cream Flavor

Flavor

Percent

0 10 20 3040506070

Chocolate

Vanilla

Strawberry

Butter Pecan

61%

19%

11%

9%

the results of a survey in which

538 students responded about their

favorite ice cream flavor.

a. Predict how many students prefer

strawberry ice cream.

b. Predict how many students

prefer chocolate ice cream.

Real-World Link

A survey found that

85% of people use

emoticons on their

instant messengers.

RRR

A

Lesson 3E Predictions 469

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