Zhang Hua's running speed is 3.5 times faster than his walking speed. He walks from home to school every day. One day, because he started 10 minutes late, he had to run half the distance, and then walk the other half distance, so that he arrived at the school at the same time as usual. So how many minutes does it take Zhang Hua to walk to school every day?
张华跑步的速度是步行速度的3.5倍，他每天从家到学校都是步行．有一天由于晚出发了10分钟，他只得跑步行了一半路程，然后步行另一半路程，这样与平时到达学校的时间一样．那么张华每天步行上学的时间是多少分钟．
<gadget id="calculator">3.5 - 1</gadget>
<output>2.5</output>

<gadget id="calculator">10 / 2.5</gadget>
<output>4</output>

<gadget id="calculator">4 * 3.5</gadget>
<output>14</output>

<gadget id="calculator">14 * 2</gadget>
<output>28</output>

<result>28</result>