i need excel formula about percentage?

Question

20% of 100 is 20
so if we add 100+20=120
but 20% of 120 is 24
and 120-24=96

i want to know that what will be the formula for that
if i deduct 20% (or any other) then i will get the awnser 100

Thanks in advance

20% of 100 is 20
so if we add 100+20=120
but 20% of 120 is 24
and 120-24=96

i want to know that what will be the formula for that
if i deduct 20% (or any other) then i will get the awnser 100

for example i i sell something in $100 and i will charge 20% (handling charges) which makes total $120.
but if the costumer return that material and ask about his payment back then i have to return him $100 (handling charges will not be pay-back). but the invoice shows me $120. and if i deduct 20% then the result is $96. and the costumer is asking for $100.
i want Microsoft Excel formula so i can return his actual amount ($100)


Thanks in advance

Answer 1

See it this way...

so, you are saying you need the formula where you give a number and a percentage (e.g. 120 and 20%) and want to obtain 100?

x = (NUMBER / (1 + PERCENTAGE))

100 = (120 / (1 + .2)) = 120 / 1.2 = 100.

Answer 2

You have to deduct 20% of the same number if you want to get the same answer every time.

As you've pointed out, 20% of 100 is not the same as 20% of 120.

And it's not logical to add or subract numbers that have different units. For the addition and subtraction to be logical, both numbers must have the same units. For example,

$100 + $20 = $120 is logical and correct, but
$100+20% = 120 is neither logical nor correct because when you add numbers with two different units, then there is no way to determine what the units for the result should be. Should it be $ or %, or both?

Answer 3

Deducting x% from an amount A leaves you with a result R given by
R = A - A*x/100
= A * (1 - x/100)
If you want to find the original amount A, we get
A = R / (1 - x/100)

In your example, A = 100 / (1 - 20/100) = 100 / (0.8) = 125.

Answer 4

20% of 125 is 25; so 125 - 25 = 100

Answer 5

the stupidiest way:

100 + 20% = 120 = 100 * 1.2
so, 120 / 1.20 = 100

280 + 15% = 280*1,50 = 322
so
322 / 1.50 = 280

Answer 6

Assume price in A1 and percentage in B1 and you want return in C1. Put the following in C1: =A1 - B1