What is the profit margin of a commodity that is marked at a 20% increase in cost and sold at a 10% discount at 270 yuan?

What is the profit margin of a commodity that is marked at a 20% increase in cost and sold at a 10% discount at 270 yuan?

Commodity cost = 270 / (100% + 20%) / 90% = 250
Profit margin = (270-250) / 250 * 100% = 8%