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Percentages

Percentages

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Percentages (%)

 

 

 

When you say "Percent" you are really saying "per 100"

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Tutorial

Percentages (%)

 

When you say "Percent" you are really saying "per 100"

 

 

So 50% means 50 per 100
(50% of this box is green)

 

And 25% means 25 per 100
(25% of this box is green)

 

     
 

 

Examples:

 

 

 

100% means all.

Example:

100% of 80 is 100/100 × 80 = 80

 

 

50% means half.

Example:

50% of 80 is 50/100 × 80 = 40

 

 

5% means 5/100ths.

Example:

5% of 80 is 5/100 × 80 = 4

 

 

   
 

A Percent can also be expressed as a Decimal or a Fraction

 

 

 

 

A Half can be written...

 
   

As a percentage:

50%

As a decimal:

0.5

As a fraction:

1/2

 

 

Some Worked Examples

Example: Calculate 25% of 80

25% = 25/100

(25/100) × 80 = 20

So 25% of 80 is 20

Example: 15% of 200 apples were bad. How many apples were bad?

15% = 15/100

(15/100) × 200 = 15 × 2 = 30 apples

30 apples were bad

Example: if only 10 of the 200 apples were bad, what percent is that?

As a fraction, 10/200 = 0.05

As a percentage it is: (10/200) x 100 = 5%

5% of those apples were bad

 

Example: A Skateboard is reduced 25% in price in a sale. The old price was $120. Find the new price

First, find 25% of $120:

25% = 25/100

(25/100) × $120 = $30

25% of $120 is $30

So the reduction is $30

Take the reduction from the original price

$120 - $30 = $90

The Price of the Skateboard in the sale is $90