There are 5 red balls, 6 white balls, and several yellow balls in the bag. If one is drawn randomly, the probability of getting a red ball is (1/3), how many yellow balls should be placed.
袋子中有5个红球，6个白球，若干个黄球，如果任意摸出一个，摸到红球的概率为(1/3)，则黄球应放多少个．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">5 / (1/3)</gadget>
<output>15</output>

<gadget id="calculator">15 - 5 - 6</gadget>
<output>4</output>

<result>4</result>