In a certain mathematics competition, (2/5) students passed the preliminary round. The average score of the students who passed the preliminary round was 12 points higher than the total average score. The average score of the students who did not pass the preliminary round was lower than the total average score by how much.
某次数学竞赛，有(2/5)的学生通过初赛，通过初赛学生的平均分比总均分高12分，没有通过初赛学生的平均分比总均分低多少分．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 * (2/5)</gadget>
<output>12</output>

<gadget id="calculator">30 - 12</gadget>
<output>18</output>

<gadget id="calculator">(2/5) / 18</gadget>
<output>1/45 = around 0.022222</output>

<gadget id="calculator">30 * (2/5) * 30 * (1/45)</gadget>
<output>8</output>

<result>8</result>