Page 475 - Basic College Mathematics with Early Integers

452 C HAPTE R 6 I PERCENT

PRACTICE 3 Example 3 Translate to an equation.

Translate: What number is
What number is 25% of 0.008?
40% of 3.6?
Solution: What number is 25% of 0.008?

5
T T T T T
n = 25% # 0.008

Work Practice 3

PRACTICE 4–6 Examples Translate each of the following to an equation:

Translate each to an equation.
4. 38% of 200 is what number?
4. 42% of 50 is what number? 5
5. 15% of what number is 9? T T T T T
38% # 200 = n
6. What percent of 150 is 90?
5. 40% of what number is 80?

5
T T T T T
40% # n = 80
6. What percent of 85 is 34?

5
T T T T T
n # 85 = 34
Work Practice 4–6

#
Concept Check In the equation 2 n = 10, what step should be taken to
solve the equation for n?

Objective Solving Percent Problems

You may have noticed by now that each percent problem has contained three
numbers—in our examples, two are known and one is unknown. Each of these
numbers is given a special name.
15% of 60 is 9
3
T T T T T
15% 60 9
# =
percent base amount

We call this equation the percent equation.

Percent Equation
#
percent base = amount

Notice that the percent equation given above is a true statement.To see this, sim-
Answers plify the left side as shown:
#
#
3. n = 40% 3.6 4. 42% 50 = n
#
15% 60 = 9 Copyright 2012 Pearson Education, Inc.
#
#
5. 15% n = 9 6. n 150 = 90
#
0.15 60 = 9 Write 15% as 0.15.
Concept Check Answer 9 = 9 Multiply.
10
If 2 # n = 10, then n = , or n = 5. The statement 9 = 9 is true.
2