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.
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.
ReplyDeleteSolution:
DeleteLet, 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