Percentage: Formula, Conversions and Examples

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Percentage is a ratio or a number represented as a fraction of 100, i.e., a fraction with 100 as the denominator. It is represented by the symbol “%”. Percentage simply is parts per 100. For example, if Shreya scored 40% in her maths exam, it means she scored 40 out of 100 marks and that can be expressed as 40/100 in fraction and as 40:100 in ratio. 

Percentage is a dimensionless quantity

Read Also: Pair of Linear Equation

Key Terms: Percentage, Percentage Formula, Decimals, Fractions, Percent Change, Percent


Percentage Formula

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In order to calculate the percentage of a number, follow the below steps:

  • Divide the value by the whole value
  • Multiply the resultant by 100  

The formula to calculate percentage is:

Percentage = (Value/Total Value) x 100

The above formula is used to calculate percentage of a quantity out of the whole quantity.

Let, A is X% of B

Then, according to the above mentioned steps

(A/B) x 100 = X%

Example: If a student got 20 out 0f 60 marks. What will be his percentage?

Solutions: Given total marks is 60 and he got 20 

Using the formula, percentage = (20/60) x 100

percentage = 33.34%

Percentage of the student is 33.34%.

Example: If a student got 120 out 0f 200 marks. What will be his percentage?

Solutions: Using the formula,

Percentage = (120/200) x 100 = 60%

Percentage scored by the student is 60%.

Example: If a girl gives away 30 mangoes out of 90 mangoes. What percentage of total mangoes is left with her?

Solutions: Remaining number of mangoes is 90 – 30 = 60

Now, using the percentage formula

Percentage = (60/90) x 100

Percentage = 66.67%

The percentage of mangoes left with the girl is 66.67%.

Some very commonly used percentages are:

  • 10% is equal to 1/10 fraction
  • 20% is equivalent to 1/5 fraction
  • 25% is equivalent to 1/4 fraction
  • 50% is equivalent to 1/2 fraction
  • 75% is equivalent to 3/4 fraction
  • 90% is equivalent to 9/10 fraction

The video below explains this:

Percentage Error Formula Detailed Video Explanation:

Also Check:


How to Calculate Percentage of a Number?

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In order to calculate what value is percentage of a number has, follow the below steps:

  1. Remove the percent “%” sign from the value and divide it by 100
  2. Multiply the resultant to the total value 

Let, A% of B is equal to X

Then, accprding to above mentioned steps

(A/100) x B = X

Example: What will be 35% of 700?

Solutions: According to the formula

Total value = 700

Percentage to find = 35%

Thus, 

(35/100) x 700 = 35 x 7 = 245

35% of 700 is 245.


Percentage Change Formula

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Whenever the value of a measured quantity changes, the change can be captured through absolute change and percentage change An absolute change is an actual change in the measured quantity and percentage change is the change in percent value. 

Percentage change is obtained by the formula: 

(Absolute value Change/ Original quantity) x 100

In simple terms, percent change is dividing the difference between old value and new value by the old value and then multiplying the result with 100. An example is given below to understand better.

Example: If Aman’s salary increased to Rs. 20,000 from Rs. 15,000, what will be the percent change?

Solutions: Given that the new salary is Rs. 20,000 while old salary was Rs. 15,000

Change in the salary = New salary – Old salary = 20,000 – 15,000

Change in the salary = Rs. 5,000 = Absolute Value

Now, using the formula, percentage 

Percentage change = (5000/15000) x 100 

Percentage change = 33.34%

Percentage change in Aman’s salary is 33.34%.

Also Read: Number System

Applications of Percentage

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Percentage is used in our day-to-day lives. Some of the important applications of percentage are: 

  • Percentage is used to compare numerical data and compare data by corporations, firms, government, schools and, colleges.
  • Percentage is used by shopkeepers and companies to calculate profit/loss percentage on the goods sold.
  • Percentage is used by Banks and financial institutions to calculate interest % on loans, fixed deposit, and savings account.
  • Economists also use percentage to calculate the growth rate, inflation rate, and tax rate of a country.
  • Percentage is also used to calculate depreciation rate on cars, trucks, and other vehicles.

Also Check:


Fraction to Percent

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In order to convert a fraction to percent, th efollowing steps must be followed:

  • Convert the fraction into decimal number
  • Multiply the resultant with 100

To understand better an example is given below:

Example: Convert 3/4 to a percent.

Solution: The decimal form of 3/4 is

0.75

Now, to get the percent we multiply the decimal number by 100

0.75 x 100 = 75%

Read More: Real Number System


Percentage Chart

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A percentage chart of fractions into percentage is given below for quick revision of students: 

Fractions Percentage
1/2 50%
1/3 33.33%
1/4 25%
1/5 20%
1/6 16.66%
1/7 14.28%
1/8 12.5%
1/9 11.11%
1/10 10%
1/11 9.09%
1/12 8.33%
1/13 7.69%
1/14 7.14%
1/15 6.66%

Things to Remember

  • Percentage mainly applies to ratios, and the percentage value of a ratio is arrived at by multiplying by 100, the decimal value of a ratio.
  • Percentage can be expressed as a decimal and a fraction.
  • Percentage is an important and simple tool for the comparison of numerical data and information.
  • Whenever the value of a measured quantity changes, the change can be captured through absolute change and percentage change, an absolute change is an actual change in the measured quantity and percentage change is the change in percent value.
  • Percentage change is obtained by the formula: (Absolute value Change/ Original quantity) x 100.

Sample Questions

Question: A student scores 20 marks out of a maximum 30 marks. Find the percentage of his marks out of the total marks. [2 marks]

Answer: His marks can then be denoted as 20 out of 30 marks and in percentage is 20/30 * 100 which is equal to 66.66%. 

Question: Define percentage. What is formula of percentage? [2 marks]

Answer: Percent means for every 100 and is derived from the French word which means 100.Percentage mainly applies to ratios, and the percentage value of a ratio is arrived at by multiplying by 100, the decimal value of a ratio. The formula of Percentage is: 

Percentage = (Value/Total Value) * 100.

Question: What is the 60 % of 300? [2 marks]

Answer: 60 % of 300 is (60/100)* 300 is 180.

Question: What percentage is 30 of 120? [3 marks]

Answer: The formula of Percentage is: 

Percentage = (Value/Total Value) * 100.

Here, Value = 30 and Total Value = 120.

So, percentage is (30/120) * 100 = 25%. 

Question: A shopkeeper sells a pen whose cost price is Rs 15 and sales price is Rs 20. The profit is Rs 5. Find the profit percentage. [3 marks]

Answer: The formula of Percentage is: 

Percentage = (Value/Total Value) * 100

Percentage = (Value/Total Value) * 100.

The profit percentage of the shopkeeper is (5/15)* 100 which is equal to 33.33%.

Question: The salary of a person is Rs 1200 and the savings is Rs 300. Find the saving percentage? [2 marks]

Answer: The formula of Percentage is: 

Percentage = (Value/Total Value) * 100

Here Value = Rs 300 and Total Value = Rs 1200

Saving Percentage is (300/1200)* 100 is 25 %.

Question: The salary of a person is Rs 1200 and the savings is Rs 300. Find the expenditure percentage? [3 marks]

Answer: Expenditure = Salary – Savings 

= 1200 – 300

= 900

The formula of Percentage is: 

Percentage = (Value/Total Value) * 100

Here Value = Rs 900 and Total Value = Rs 1200

Saving Percentage is (900/1200)* 100 is 75 %.

Question: If 10% of a is 40. Find a. [2 marks]

Answer: 10 % of a = 40

10a/100 = 40

a = 400.

Question: Find the interest on Rs 800 if the interest rate is 10%? [2 marks]

Answer: Interest = Rs 800 and Interest Rate = 10%

Interest Amount = (800*10)/100 is Rs 80.

Question: What will be the value of 175% of 100? [2 marks]

Answer: 175% of 100 = (175/100) x 100 = 175

Hence, 175% of 100 will be 175. 


Also Read:

CBSE X Related Questions

1.
Find the sums given below :
  1. \(7 + 10\frac 12+ 14 + ....... + 84\)
  2. \(34 + 32 + 30 + ....... + 10\)
  3. \(–5 + (–8) + (–11) + ....... + (–230)\)

      2.

      Form the pair of linear equations for the following problems and find their solution by substitution method.

      (i) The difference between two numbers is 26 and one number is three times the other. Find them.

      (ii) The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.

      (iii) The coach of a cricket team buys 7 bats and 6 balls for Rs 3800. Later, she buys 3 bats and 5 balls for Rs 1750. Find the cost of each bat and each ball.

      (iv) The taxi charges in a city consist of a fixed charge together with the charge for the distance covered. For a distance of 10 km, the charge paid is Rs 105 and for a journey of 15 km, the charge paid is Rs 155. What are the fixed charges and the charge per km? How much does a person have to pay for travelling a distance of 25 km.

      (v) A fraction becomes\(\frac{ 9}{11}\), if 2 is added to both the numerator and the denominator. If, 3 is added to both the numerator and the denominator it becomes \(\frac{5}{6}\). Find the fraction.

      (vi) Five years hence, the age of Jacob will be three times that of his son. Five years ago, Jacob’s age was seven times that of his son. What are their present ages?

          3.
          If 3 cot A = 4, check whether \(\frac{(1-\text{tan}^2 A)}{(1+\text{tan}^2 A)}\) = cos2 A – sinA or not

              4.

              Solve the following pair of linear equations by the substitution method. 
              (i) x + y = 14 
                  x – y = 4   

              (ii) s – t = 3 
                  \(\frac{s}{3} + \frac{t}{2}\) =6 

              (iii) 3x – y = 3 
                    9x – 3y = 9

              (iv) 0.2x + 0.3y = 1.3 
                   0.4x + 0.5y = 2.3 

              (v)\(\sqrt2x\) + \(\sqrt3y\)=0
                  \(\sqrt3x\) - \(\sqrt8y\) = 0

              (vi) \(\frac{3x}{2} - \frac{5y}{3}\) =-2,
                  \(\frac{ x}{3} + \frac{y}{2}\) = \(\frac{ 13}{6}\)

                  5.
                  A 1.5 m tall boy is standing at some distance from a 30 m tall building. The angle of elevation from his eyes to the top of the building increases from 30° to 60° as he walks towards the building. Find the distance he walked towards the building.

                      6.

                      A vertical pole of length 6 m casts a shadow 4 m long on the ground and at the same time a tower casts a shadow 28 m long. Find the height of the tower.

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