·
Percentage is a method of representing any
quantity in fraction of 100 i.e. out of 100 how much is that quantity.
·
It is often denoted using the percent
sign, "%"
·
One percent (1%) means 1 per 100 and 100%
means all and so on..
Points
to Remember:
·
^{1}/_{5}^{th} of a number =
^{1}/_{5}_{ }×100 = 20%
·
20% of a mumber = ^{20}/_{100} = ^{1}/_{5}^{th} of that number.
·
If a number is increased from value A to B
then % increase = ^{(BA)}/_{A} × 100
·
If
a number is decreased from value A to B then % decrease = ^{(AB)}/_{A} ×100
_{·
}If x% and y% are two successive increase(+ve) or decrease(ve)
in a number then overall percentage of
change = x + y + ^{xy}/_{100}
·
If
the population of a city increases (+ve) or decreases(ve) by r% every year then,
^{
I.
}Population after n year = Present Population ×(1+
^{r}/_{100})^{n}^{}
II.
Population
n years ago = Present Population ×(^{100}/_{(100+r)})^{n}
·
What
is the percent value A to B = ^{A}/_{B }× 100
Now let’s understand each of above listed
point with examples one by one.
Example:
Calculate 25% of 80
25% =

25

100

And

25

× 80 = 20

100

So 25% of 80 is 20
Example:
A
fruit seller had some apples. He sells 40% apples and still has 420 apples.
Originally, he had:
Explanation:
Suppose originally he had x apples.
Then, (100  40)% of x = 420.
60  x x = 420  
100 
x =  420 x 100  = 700.  
60 
Example:
If the population of a city increases 20% every
year and if its present population is 576000. What was the population of city 2
years ago.
Explanation:
This is an example of two successive change.
Population
n years ago =Present Population ×(^{100}/_{(100+r)})^{n}
= 576000×(^{100}/_{(100+20}_{)})^{n}
= 400000
Example:
What
percentage of 5 is 3
Explanation:
=^{3}/_{5}×100
= 60%