The probability of finding a red ball in an opaque pocket is (1/5). If there are 3 red balls in the pocket, how many balls are there in the pocket?
在一个不透明的口袋中摸出红球的可能性为(1/5)，已知口袋中的红球是3个，则袋中一共有多少个球．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<result>15</result>