There are 10 first prizes, 20 second prizes, 30 third prizes and 200 encouragement prizes in a lottery box. So what are the chances of getting the third prize?
一个抽奖箱里放了10个一等奖，20个二等奖，30个三等奖，200个鼓励奖．那么摸到三等奖的可能性是多少
<gadget id="calculator">10 + 20 + 30 + 200</gadget>
<output>260</output>

<gadget id="calculator">30 / 260</gadget>
<output>3/26 = around 0.115385</output>

<result>3/26 = around 0.115385</result>