Zhao Qiang arrives at school every day after walking for 10 minutes and running for 2 minutes. One day he started running after walking for 6 minutes, and it turned out to be 2 minutes and 24 seconds early. How many times his running speed was his walking speed.
赵强每天上学步行10分钟以后，跑步2分钟，恰好到校．有一天他步行6分钟后就开始跑步，结果早到了2分24秒，他跑步速度是步行速度的多少倍．
<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<gadget id="calculator">10 + 2</gadget>
<output>12</output>

<gadget id="calculator">6 + 2.4</gadget>
<output>8.4</output>

<gadget id="calculator">12 - 8.4</gadget>
<output>3.6</output>

<gadget id="calculator">3.6 - 2</gadget>
<output>1.6</output>

<gadget id="calculator">4 / 1.6</gadget>
<output>2.5</output>

<result>2.5</result>