Fresh mushrooms lose 90% of their original weight after being dried, and there are 20 kilograms of dried mushrooms. If you ask "how many kilograms of fresh mushrooms are dried", how can the formula be listed?
鲜蘑菇经晾晒后失去原重量的90%，现有干蘑菇20千克，要求"这是由多少千克鲜蘑菇晾晒成的"，算式可以怎样列多少
<gadget id="calculator">90 / 100</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">20 / (1/10)</gadget>
<output>200</output>

<result>200</result>