Percentage online test - Aptitude

Here we provided formulae and hints for Percentage category. Requesting you to read the below points before taking online test.

Normally Percentage is defined as the fraction having denominator is 100 and numerator of the fraction is called rate of percent.

Percentage is denoted by ‘%’ symbol.

Percentage Questions And Answer

Some Tricks and Tips on Percentage

Tip-1

X % of Y ⇒ $ {X / 100} × Y $

X % of Y = Y % of X

Tip-2

If the new value of something is n times the previously given value, then the percentage increase is (n-1) × 100%

Example

Question-1)

If X= 2.15 Y, then find the percentage increase when the value of something is from Y to X.

Solution:

Use the formula: (n-1)×100% Percentage increase from Y to X = (2.15 -1)× 100= 115%

Tip-3

When a quantity N is increased by K %, then the:
New quantity = N $ (1+ K/100 )$

Example

Question-2)

What is the new value when 265 is increased by 15%?

Solution:

New quantity = N $(1+ K/100)$= 265$(1+15/100)$
New quantity = 1.15 ×265= 304.75

Tip-4

When a quantity N is decreased by K %, then the: New quantity =N $(1 – K/100)$

Example

Question-3)

If the production in 2022 is 3400 units and the decrease from 2020 to 2022 is 27%, find the production in 2020.

Solution:

New quantity = N $(1 – K/100)$= 3400$(1-27/100)$
New quantity = 3400 × 0.73= 2482

Tip-5

To calculate the percentage change in value

Percentage change = $ {\text"Change"}/{\text"Initial value"} × 100$

Tip-6

If the income of a man is A% more than another man, then the income of another man is less in comparison to the 1st man by

Or, we can Say by Another Way

If the cost of an product is increased by A%, then how much to decrease the consumption of product , so that expenditure remains same is given by

$(P/{100 + P} × 100)%$

Tip-7

If 'x' is A% less than 'y', then y is more than 'x' by

Or we can say by another way

If the cost of an article is decreased by A%, then the increase in consumption of article to maintain the expenditure will be?

$(A/{100 - A} × 100)%$ (increase)

Tip-8

If value of an object/number/population P is successively changed by x%, y% and then z% in first, second and third year

Then, the object/number/population changes after 3 years = P$(1 ± {x}/100)(1 ± {y}/100)(1 ± {z}/100)$

'+' is used when population increases

'–' is used when population decreases.

Both percentage changes are positive:
x and y are positive and net increase = $(x+y+{xy}/{100})$ %.

One percentage change is positive and the other is negative:
x is positive and y is negative, then net percentage change = $(x-y-{xy}/{100})$%

Both percentage changes are negative:
x and y both are negative and imply a clear decrease= $(-x-y+{xy}/{100})$%

Example

Question-4)

A’s salary is increased by 10% and then decreased by 10%. The change in salary is

Solution:

Percentage change formula when x is positive and y is negative = $({x – y – ({xy}/{100})})$%
Here, x = 10, y = 10
= $(10 – 10 – {(10 × 10)}/{100}) $= -1%
As negative sign shows a decrease, hence the final salary is decreased by 1%.

Tip-9

If an amount is increased by a% and then it is reduced by a% again,

Then percentage change will be a decrease of $a^2/100%$

Example

Question-5)

The tax imposed on an article is decreased by 10% and its consumption increases by 10%. Find the percentage change in revenue from it.

Solution:

If an amount is increased by a% and then it is reduced by a% again, then the percentage change will be a decrease of $a^2/100$%

Required change = $(10)^2/100%$ decrease

= 1% decrease