A shopping mall increases the price of a certain product by 50% of the purchase price, and then sells it at a 20% discount for promotion. As a result, each product still makes a profit of 20 yuan. How much is the purchase price of each product?
一商场将某种商品按进价的50%加价后，为促销又打八折出售，结果每件商品仍获利20元，请问每件商品进价为多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/5) * (1/2)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) - 1</gadget>
<output>-3/5 = around -0.6</output>

<gadget id="calculator">(4/5) + (-3/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>