Due to the adoption of new technology in a factory, the selling price of each product is now 100 yuan, and the cost is 40 yuan, which is 20% lower than the original cost. How much is the original cost of each product?
一个工厂由于采用新工艺，现在每件产品的售价为100元，成本为40元，比原来的成本降低了20%，原来每件产品的成本是多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 / (4/5)</gadget>
<output>50</output>

<result>50</result>