The correspondent originally planned to travel 60 kilometers in 2.5 hours, but actually only took 2 hours. How many kilometers per hour is actually more? How many.
通讯员原计划2.5小时行60千米，实际只用了2小时．实际每小时多行多少千米？多少．
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">60 / 2.5</gadget>
<output>24</output>

<gadget id="calculator">30 - 24</gadget>
<output>6</output>

<result>6</result>