Hu Jun set off from his home to the county town by motorcycle at a speed of 700 m/min and arrived in 30 minutes; after finishing his business, he returned by the same road and arrived home in 35 minutes. What was the speed in meters per minute when he returned?
胡军骑摩托车从家出发去县城，行驶的速度是700米/分，30分钟到达；办完事后按原路返回，用了35分钟到家．他返回时行驶的速度是多少米/分钟？
<gadget id="calculator">30 / 35</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">700 * (6/7)</gadget>
<output>600</output>

<result>600</result>