In Class 3 of Grade 5, Xiao Yu needs (5/7) votes to be elected as a class leader. After counting (5/8) of the votes, he got (7/10) of the number of votes to be elected, so what percentage of the remaining votes does he need to get to be elected?
五年级三班在一次班长选举中，肖宇同学需(5/7)的选票方能当选．计算了(5/8)的选票后，他得到了当选票数的(7/10)，那么他还需得到剩下选票的几分之几能当选？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (7/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/10) / (3/8)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(5/7) * (4/5)</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>