If a product is sold at a reduced price according to the season, if the price is reduced by 10% according to the current price, it can still make a profit of 50 yuan; if the price is reduced by 20%, it will lose 40 yuan. What is the current price of this item.
一件商品随季节变化降价出售，如果按现价降价10%，仍可盈利50元；如果降价20%，就要亏损40元．这件商品的现价是多少元．
<gadget id="calculator">50 + 40</gadget>
<output>90</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/5) - (1/10) - 1</gadget>
<output>-9/10 = around -0.9</output>

<gadget id="calculator">1 + (-9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">90 / (1/10)</gadget>
<output>900</output>

<result>900</result>