At the graduation party, the students watched the wonderful performance on the stage. Some of the audience under the stage were standing and the other part was sitting. If 25% of the standing people sit down and 25% of the sitting people stand up, then the standing people account for (3/5) of the audience. What percentage of the total number of spectators was the standing audience?
在毕业联欢会上同学们观看舞台上的精彩表演，舞台下的观众有一部分站着，另一部分坐着．如果站着的人中有25%坐下，而坐着的人中有25%站起来，那么站着的人就占观众的(3/5)．原来站着的观众占观众总人数的几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(3/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<result>7/20 = around 0.35</result>