Formula to calculate a percentage

What is a percentage?

A percentage is a way to define a part, or fraction of a total.

When we discuss percentages, we should ask ourselves the following: "the percentage of what?". Saying 50% without specifying the whole, fails to make sense. Instead one should say " 50% 50\% of 80 80 " is 40 40 . In summary, the percentage represents what part of 100 100 is the number in question.

The percentage symbol is % \% :
When we want to express that a%a\%
We should write it as follows: a100a \over 100

In order to solve percentage problems, we apply the following formula

Percentage valueInitial amount=The percentage100 \frac{Percentage~value}{Initial~amount}=\frac{The~percentage}{100}

Percentage value: is the actual value that this percentage represents.

Initial amount: is the initial figure before being changed.
Percentage: is the percentage of change.

B - To solve percentage problems, we will use the following formula

You can apply this formula to any percentage exercise, as long as you note the data correctly, and verify what has been asked.


Practice Percentage

Examples with solutions for Percentage

Exercise #1

Calculate 6% of 100:

Video Solution

Step-by-Step Solution

To solve the problem of calculating 6% of 100, we follow these clear steps:

  • Step 1: Convert the percentage to a fraction. The percentage 6% is equivalent to the fraction 6100 \frac{6}{100} .
  • Step 2: Multiply the whole number by this fraction. We calculate 6100×100 \frac{6}{100} \times 100 .
  • Step 3: Perform the calculation. Simplifying 6100×100 \frac{6}{100} \times 100 , we find:
6×100100=6 \frac{6 \times 100}{100} = 6

Therefore, the solution to the problem is 6.

Answer

6

Exercise #2

Calculate 3% of 100:

Video Solution

Step-by-Step Solution

To solve this problem, we'll proceed with the following steps:

  • Step 1: Identify the given information
    We are given a percentage of 3% and a whole number of 100.
  • Step 2: Use the percentage formula
    The formula to calculate the percentage of a whole number is given by:
    Percentage value=percentage100×whole number \text{Percentage value} = \frac{\text{percentage}}{100} \times \text{whole number}
  • Step 3: Substitute the values and calculate
    Substituting the given values into the formula, we have:
    3100×100=3 \frac{3}{100} \times 100 = 3

Therefore, the 3% of 100 is 3 3 .

Answer

3

Exercise #3

Calculate 32 over 100 as a percentage:

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the given fraction 32100 \frac{32}{100} .
  • Step 2: Recognize that the denominator of 100 aligns directly with the meaning of percentage.
  • Step 3: Conclude that when the fraction is Part100 \frac{\text{Part}}{100} , it equals Part% \text{Part}\% .

Now, let's work through each step:

Step 1: The problem gives us the fraction 32100 \frac{32}{100} .
Step 2: Since the denominator is 100, the fraction directly represents a percentage.
Step 3: This means that 32100 \frac{32}{100} is simply 32% 32\% .

Therefore, the solution to the problem is 32% 32\% .

Answer

32%

Exercise #4

Calculate 40 over 100 as a percentage:

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Use the percentage formula: (PartWhole)×100%\left(\frac{\text{Part}}{\text{Whole}}\right) \times 100\%.
  • Step 2: Substitute the given numbers: (40100)×100%\left(\frac{40}{100}\right) \times 100\%.
  • Step 3: Calculate the division, 40100=0.4\frac{40}{100} = 0.4.
  • Step 4: Multiply by 100 to convert to a percentage: 0.4×100=40%0.4 \times 100 = 40\%.

Therefore, 40 over 100 as a percentage is 40%40\%.

Answer

40%

Exercise #5

Calculate 15% of 100:

Step-by-Step Solution

To find 15% of 100, you can convert the percentage to a decimal by dividing by 100:

15%=15100=0.15 15\% = \frac{15}{100} = 0.15

Next, multiply this decimal by 100:

0.15×100=15 0.15 \times 100 = 15

Thus, 15% of 100 is 15.

Answer

15 15

Exercise #6

Calculate 8% of 100:

Step-by-Step Solution

To find 8% of 100, first convert the percentage to a decimal by dividing by 100:

8%=8100=0.08 8\% = \frac{8}{100} = 0.08

Then, multiply this decimal by 100:

0.08×100=8 0.08 \times 100 = 8

Hence, 8% of 100 is 8.

Answer

8 8

Exercise #7

Calculate 45% of 100:

Step-by-Step Solution

To find 45% of 100, you can multiply the percentage as a decimal by the whole number. First, convert 45% into a decimal. This is done by dividing by 100: 45%=45100=0.45 45\% = \frac{45}{100} = 0.45 .

Then, multiply this decimal by 100: 0.45×100=45 0.45 \times 100 = 45 .

Therefore, 45% of 100 is 45 45 .

Answer

45 45

Exercise #8

Calculate 35% of 100:

Step-by-Step Solution

To find 35% of 100, first convert the percentage into a decimal by dividing by 100: 35%=35100=0.35 35\% = \frac{35}{100} = 0.35 .

Then, multiply this decimal by 100: 0.35×100=35 0.35 \times 100 = 35 .

Therefore, 35% of 100 is 35 35 .

Answer

35 35

Exercise #9

Calculate 25 over 100 as a percentage:

Step-by-Step Solution

In order to determine what percentage 25 is out of 100, we use the following formula:

Percentage=PartWhole×100% \text{Percentage} = \frac{\text{Part}}{\text{Whole}} \times 100\%

.

We begin by substituting in the known values:

Percentage=25100×100%=25% \text{Percentage} = \frac{25}{100} \times 100\% = 25\%

.

Thus, 25 out of 100 is 25% 25\% .

Answer

25%

Exercise #10

Calculate 75 over 100 as a percentage:

Step-by-Step Solution

In order to determine what percentage 75 is out of 100, we use the following formula:

Percentage=PartWhole×100% \text{Percentage} = \frac{\text{Part}}{\text{Whole}} \times 100\%

.

We begin by substituting in the known values:

Percentage=75100×100%=75% \text{Percentage} = \frac{75}{100} \times 100\% = 75\%

.

Thus, 75 out of 100 is 75% 75\% .

Answer

75%

Exercise #11

Calculate 10 over 100 as a percentage:

Step-by-Step Solution

In order to determine what percentage 10 is out of 100, we use the following formula:

Percentage=PartWhole×100% \text{Percentage} = \frac{\text{Part}}{\text{Whole}} \times 100\%

.

We substitute in the known values:

Percentage=10100×100%=10% \text{Percentage} = \frac{10}{100} \times 100\% = 10\%

.

Thus, 10 out of 100 is 10% 10\% .

Answer

10%

Exercise #12

Calculate 40 over 100 as a percentage:

Step-by-Step Solution

In order to determine what percentage 40 is out of 100, we use the following formula:

Percentage=(PartWhole)×100 \text{Percentage} = \left( \frac{\text{Part}}{\text{Whole}} \right) \times 100

We begin by substituting in the known values:

Percentage=(40100)×100 \text{Percentage} = \left( \frac{40}{100} \right) \times 100

We then proceed to solve the expression:

Percentage=0.4×100 \text{Percentage} = 0.4 \times 100

Percentage=40 \text{Percentage} = 40

Thus, 40 out of 100 is 40%.

Answer

40%

Exercise #13

Calculate 65 over 100 as a percentage:

Step-by-Step Solution

To find what percentage 65 is out of 100, use the formula:

Percentage=(PartWhole)×100 \text{Percentage} = \left( \frac{\text{Part}}{\text{Whole}} \right) \times 100

Substitute the given values:

Percentage=(65100)×100 \text{Percentage}=\left(\frac{65}{100}\right)\times100

Solve the expression:

Percentage=0.65×100 \text{Percentage}=0.65\times100

Percentage=65 \text{Percentage}=65

So, 65 out of 100 is 65%.

Answer

65%

Exercise #14

Calculate 20% of 100:

Step-by-Step Solution

In order to determine 20% of 100, we begin by converting the percentage into a decimal and then proceed to multiply by the whole number. First, convert 20% to a decimal: 20%=0.2 20\% = 0.2

Next, multiply this decimal by 100 to find the percentage of the whole number: 0.2×100=20 0.2 \times 100 = 20

Thus, 20% of 100 is 20 20 .

Answer

20 20

Exercise #15

Calculate 95% of 100:

Step-by-Step Solution

In order to calculate 15% of 100, start by converting the percentage into a decimal. Convert 15% to a decimal: 95%=0.95 95\% = 0.95

Then multiply the decimal by 100 to find the percentage value: 0.95×100=95 0.95 \times 100 = 95

So, 95% of 100 is 95 95 .

Answer

95 95