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

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.