There are 15 white and red balls of the same size in a pocket. It is known that the probability of touching a white ball is (3/5), how many red balls are in the pocket.
一个口袋中装有大小相同的白球和红球共15个，已知摸到白球的可能性是(3/5)，则口袋里红球装了多少个．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">15 * (3/5)</gadget>
<output>9</output>

<gadget id="calculator">15 - 9</gadget>
<output>6</output>

<result>6</result>