Page 474 - Basic College Mathematics with Early Integers

6.2 SOLVING PERCENT PROBLEMS USING EQUATIONS Objectives

Write Percent Problems
as Equations.
Note: Sections 6.2 and 6.3 introduce two methods for solving percent problems. It is
not necessary that you study both sections. You may want to check with your Solve Percent Problems.
instructor for further advice.
Throughout this text, we have written mathematical statements such as
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3 + 10 = 13, or area = length width. These statements are called “equations.” An
equation is a mathematical statement that contains an equal sign. To solve percent
problems in this section, we translate the problems into such mathematical state-
ments, or equations.

Objective Writing Percent Problems as Equations

Recognizing key words in a percent problem is helpful in writing the problem as an
equation. Three key words in the statement of a percent problem and their mean-
ings are as follows:
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of means multiplication 1 2
is means equals 1=2
what (or some equivalent) means the unknown number
In our examples, we let the letter n stand for the unknown number.

Any letter of the alphabet can be used to represent the unknown number. In this
section, we use the letter n.

Example 1 Translate to an equation. PRACTICE 1
Translate: 6 is what percent
5 is what percent of 20?
of 24?
Solution: 5 is what percent of 20?

5
T T T T T
5 = n # 20
Work Practice 1

Remember that an equation is simply a mathematical statement that contains an
equal sign 1=2.
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5 = n 20
c
equal sign

Example 2 Translate to an equation. PRACTICE 2

Translate: 1.8 is 20% of what
1.2 is 30% of what number?
number?
Solution: 1.2 is 30% of what number?
5
T T T T T
1.2 = 30% # n Answers
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Work Practice 2 1. 6 = n 24 2. 1.8 = 20% # n
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