Solve Percent Problems

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Percent ProblemscentPer

Means to form a ratio written in a fraction format

Means 100

So 15 percent (15%) means 15/100

A percent is the ratio of a number to 100.

6100 = 6%

Write the percent modeled by the grids below

= 25%25

100= 63%

63

100

Sloths may seem lazy, but their extremely slow movement helps to make them almost invisible to predators. 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.

Proportion Method Equation Methodn

100= 16.5

24PartWhole

PartWhole

What percent of 24 is 16.5?

n · 24 = 100 · 16.5

24n = 1,650

n = 68.75

n · 24 = 16.5

n = 0.6875

n = 68.75%

Sloths spend about 69% of the day sleeping!

EX 1)

Set up a proportion.

Multiply.

Divide each side by 25 to isolatethe variable.

%100

=PartWhole

%100

= IsOf

15 is 25% of what number?

25100

= 15n

25n = 1,500

25n25

= 1,500 25

n = 60 15 is 25% of 60.

0 10% 50% 100%

0 6015

25%

30

What percent of 50 is 10?

n100

= 1050

n · 50 = 100 · 10

50n = 1,000

50n50

= 1,000 50

n = 20

10 is 20% of 50.

Write a proportion.

Set the cross products equal.

Multiply.

Divide each side by 50 to isolatethe variable.

EX 2)

0 10% 50% 100%

0 50255

20%

10

What is 40% of 20?

40100

= 8n

n · 40 = 100 · 8

40n = 800

40n40

= 800 40

n = 20

8 is 40% of 20.

Write a proportion.

Set the cross products equal.

Multiply.

Divide each side by 40 to isolatethe variable.

EX 3)

0 10% 50% 100%

0 10

40%

202 8

Notes start here

Solve Percent Problems

You need two different colored highlighters

Not all slides used in notes

Date _____________

EX 1) 15 is 25% of what number?

0 10% 50% 100%

0

25%

What percent of 50 is 10?EX 2)

0 10% 50% 100%

0

What is 40% of 20?EX 3)

0 10% 50% 100%

0