An expedition team originally planned to walk 40 kilometers a day and reach the destination in 8 days. Due to work needs, they walked an extra 10 kilometers a day. What percentage of the actual time was shortened?
一个探险队原计划每天走40千米，8天到达目的地，由于工作需要，每天多走10千米，实际所用时间缩短了百分之几？
<gadget id="calculator">40 * 8</gadget>
<output>320</output>

<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<gadget id="calculator">320 / 50</gadget>
<output>32/5 = around 6.4</output>

<gadget id="calculator">8 - (32/5)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">(8/5) / 8</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>