Formula: purchase price = selling price-selling price * profit rate, selling price = purchase price/profit rate, profit = selling price-buying price, profit rate = (selling price-buying price) ÷ selling price, selling price = selling price, buying price = buying price.

For example:

It costs 3000 yuan to buy a computer.

The selling price is 3500 yuan (selling price)

3500-3000=500 (profit)

Need to know:

Purchase price: usually refers to the "purchase price including tax" (note: the computer system actually calculates the gross profit based on the "purchase price excluding tax"), and the factors that determine the purchase price include: "the quality and negotiation skills of buyers and sellers, the strength of buyers and sellers, supply and demand, payment terms and other transaction conditions and requirements.

Supplier's regional marketing strategy, supplier's profitability, and buyer's market positioning, or purchase quantity, raw material price, exchange rate and so on. "Purchase price including tax" refers to the purchase price after deducting "discount" on the computer system.