Excel formula for reverse percentage calculation

Question

I have a calculation which I am unable to crack.

Lets say my Cost Price is 300. I want to sell the item at No Profit or No Loss. My total commission/expenses will be

Answer 1

I was looking for a similar equation/formula, but then I built it in Excel.

So if you have, say, an item with

CostPrice = 200

Then you add a ProfitMargin = 20% so the

SellPrice = 200 + 20% = 240

Then the reverse equation for this will be

CostPrice = ( SellingPrice * 100 ) / ( ProfitMargin + 100 )

// In your case it should be
CostPrice = ( 390 * 100 ) / ( 30 + 100 )
          = 300

See it in action :)

Answer 2

You want Sell Price - 30% Sell Price = Cost Price.

Combining the left two, you have 70% Sell Price = Cost Price.

Divide both sides by 70% and you get Sell Price = (1/0.7) Cost Price.

The fraction 1/0.7 is approximately 1.42857.

Answer 3

the formula you want is

=300/0.7

or

=300/(1-30%)

basically it is 300= x*(1-.30) where the (1-.30) is the amount that wants to be kept after the commision of 30%. Solving for x we get the above formula.