Percentage | What is percentage?

Percentage

Percentage | What is percentage?

Percentage is the rate per hundred and percent means per hundred i.e. out of hundred. For example 15 percent means 15 out of 100. A percentage is a fraction having the denominator 100. The symbol to denote percent is % of any fraction. Say, 4/25 is equivalent to 16/100 which denotes 16%.


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To convert fraction or decimal into percent:

To convert a fraction or decimal into percent we have to multiply by 100%.
For example: 3/10 = 3/10 × 100% = 30%
                      Similarly,
                      0.36 = 0.36 × 100% = 36%

To convert a percent into fraction:

To convert a percent into fraction we have to divide by 100.
For example: 46% = 46/100 = 23/50
                      Similarly,
                      7.5% = 7.5/100 = 75/1000 = 3/40


To find the percent of quantities:

To find the percent of quantities we convert the percent into fraction and multiply with total quantity.
For example: Take 32% of Rs. 75
                      = 32/100 × Rs. 75
                      = Rs. 24


Workout Examples

Example 1: Among 225 candidates, 20% failed. Find the number of candidates who passed.

Solution: Here,
                        Total candidates = 225

                        Failed = 20% of 225
                                   = 20/100 × 225
                                   = 45

                        Passed = Total – failed
                                       = 225 – 45
                                       = 180


Example 2: A boy gets 25 marks out of 75. What percent of marks does he get?

Solution: Here,
                  A boy gets 25 out of 75

He got  = 25/75 × 100%
            = 100/3%
            = 33.33%


Example 3: There are 6000 mangoes in a fruit shop, among them 1500 are sold. What percent of mangoes are unsold?

Solution: Here,
                        Total mangoes = 6000
                        Sold mangoes = 1500
                        Unsold mangoes  = 6000 – 1500
                                                        = 4500

Unsold percent  = 4500/6000 × 100%
                              = 25%


Example 4: 25% of total students in a school are boys. If 150 students were girls, find the number of boys.

Solution: Here,
                        Percent of boys = 25%
                        Percent of girls = 100 – 25% = 75%
                        No. of girls = 150
                        Let, total students = x

                     75% of x = 150
            or,        75/100 × x = 150
            or,        x = 150 × 100/75
            or.        x = 200

            Total students = 200

No. of boys = 200 – 150
                       = 50


Example 5: The price of petrol is increased from Rs. 105 per litre to Rs. 125 per litre, what percent is increased?

Solution: Here,
                        Increased price = Rs. 125 – 105
                                                   = Rs. 20

                        Increased percent = 20/105 × 100%
                                                          = 100/7%
                                                          = 19.05%


You can comment your questions or problems regarding the percentage here.

2 comments:

  1. in an election between two candidates, 20% of the registered voters did not cast their vote and 40 votes were declared invalid. the winner received 42% of the registered votes and was declared the winner by 112 votes. what was the number of registered voters.

    ReplyDelete
    Replies
    1. Solution:
      Let, no of registered voters = x
      Did not cast = 20% of x = 20x/100
      Invalid votes = 40
      Winner = 42% of x = 42x/100
      Loser = 42% of x – 112 = 42x/100 – 112

      ∴ 20x/100 + 40 + 42x/100 + 42x/100 – 112 = x
      or, 104x/100 – x = 72
      or, 4x/100 = 72
      or, 4x = 7200
      or, x = 7200/4
      or, x = 1800
      ∴ No of registered voters = 1800

      Delete