If a commodity is sold at a 10% discount on the price, a profit of 20% can be obtained. The purchase price of this commodity is 210 yuan per piece, so what is the price of each commodity?
一种商品按标价的九折销售，可获得利润20%，该种商品的进价为每件210元，则每件商品的标价为多少元．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">210 * (6/5)</gadget>
<output>252</output>

<gadget id="calculator">252 / 0.9</gadget>
<output>280</output>

<result>280</result>