In a box there are 3 black balls, 5 red balls and 4 white balls. Draw a ball randomly, the probability of drawing a black ball is ((())/(())), and the probability of drawing a red ball is ((())/(())). If one ball is drawn out of it each time, and then put in again, and repeated 60 times, how many times are white balls drawn out?
在一个盒子里放有3个黑球，5个红球，4个白球．从中任意摸出一个球，摸出黑球的可能性是((())/(()))，摸出红球的可能性是((())/(()))．如果从中每次摸出一个球，再放进去，重复60次，大约有多少次摸出白球．
<gadget id="calculator">3 + 5 + 4</gadget>
<output>12</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / (1/4) / 12</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">60 * (1/3)</gadget>
<output>20</output>

<result>20</result>