TNPSC – PERCENTAGE

TNPSC – PERCENTAGE

Percentage:

Percentage in mathematics, means to convert a given fraction to a denominator of 100.

It is often denoted using the percent sign, “%”.

For example, 65% (read as “forty five percent”) is equal to = 65/100 = 0.65

==> If A is x% greater than B, then B will be

lesser than A.

==> If A is x% lesser than B, then B will be

greater than A.

==> Percentage Increase (↑)

If final value is more than initial value, there is increase

% increase ↑ = increased value / initial value

Increased value = Final Value – Initial value.

If there is ‘P’ % increase, then the final value is found by multiplying the initial value by (1+  )* IV

Increase 20 by 5% à [1+ (5/100)]*20 à (105/100)*20 = 21

==> Percentage Decrease (↓)

If final value is less than initial value, there is decrease

% decrease ↑ = decreased value / initial value

Decreased value = Initial value – Final Value

If there is ‘P’ % decrease, then the final value is found by multiplying the initial value by (1-  )* IV

Decrease 120 by 25% à [1- (25/100)]*120 à (75/100)*120 = 90

==> Population:

To find the population of a city after n years = P {1+ (R/100) }ⁿ

To find the population of a city n years ago = P / {1+ (R/100) }ⁿ

==> Depreciation:

To find the Depreciation of a product after n years = P {1- (R/100) }ⁿ

To find the Depreciation of a product n years ago = P / {1- (R/100) }ⁿ