From a bag containing 20 red balls and yellow balls, draw out a ball each time, write down the color and then put it into the bag, shake it well and touch again, so touch 10 times in total, and touch 4 yellow balls in total Next, please calculate how many red balls there may be in the bag according to this situation.
从一个装有20个红球和黄球的袋中，每次摸出一个球，记下颜色后再放入袋中，摇匀再摸，这样共摸10次，其中共摸到黄球4次，请根据这一情况，计算袋中红球可能有多少个．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">20 * (3/5)</gadget>
<output>12</output>

<result>12</result>