A shopping mall sells a certain product due to changing seasons. If it is sold at 50% off the price, it will lose 30 yuan. If it is sold at 10% off the price, it will earn 10 yuan. How much is the price of this product?
某商场因换季销售某种商品，如果按定价的五折出售，将赔30元，如果按定价的九折出售，将赚10元．该商品的定价为多少元？
<gadget id="calculator">30 + 10</gadget>
<output>40</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

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

<gadget id="calculator">(9/10) - (1/2)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 / (2/5)</gadget>
<output>100</output>

<result>100</result>