For a commodity, if the current price is reduced (1/10), the profit may still be 200 yuan; if the price is reduced (1/5), the loss is 220 yuan. How much is the purchase price of this item?
一种商品，如果按现价降低(1/10)，仍可能利200元；如果降价(1/5)，则亏损220元．这件商品进价是多少元？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 * (1/5)</gadget>
<output>40</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">220 * (1/10)</gadget>
<output>22</output>

<gadget id="calculator">220 - 40 - 22</gadget>
<output>158</output>

<gadget id="calculator">200 + 158</gadget>
<output>358</output>

<gadget id="calculator">1 - 1 - (1/10)</gadget>
<output>-1/10 = around -0.1</output>

<gadget id="calculator">(1/5) + (-1/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">358 / (1/10)</gadget>
<output>3_580</output>

<result>3_580</result>