The purchase price of a soybean milk machine in Renxing Commercial Building plus 40 yuan is the fixed price. Later, it was sold at a profit, and Aunt Li bought one at 80% of the price, and the commercial building made a profit of 12 yuan. How much is the purchase price of this soybean milk machine?
仁兴商厦一款豆浆机的进价加上40元是定价．后来让利销售，李阿姨按定价的80%买了一台，商厦还盈利12元．这款豆浆机的进价是多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 * (4/5)</gadget>
<output>32</output>

<gadget id="calculator">32 - 12</gadget>
<output>20</output>

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

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

<result>100</result>