A set of data is arranged in descending order: 2, 4, 5, x, 7, 7, 8, 15. It is known that the median of this set of data is 7, what is the mode of this set of data
一组数据按从小到大排列为：2，4，5，x，7，7，8，15．已知这组数据的中位数是7，这组数据众数是多少
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">7 - (7/2)</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(7/2) / (1/2)</gadget>
<output>7</output>

<result>7</result>