Li Hua started from the school and walked at a speed of 4 kilometers per hour to report to the winter camp 20.4 kilometers away. Half an hour later, the camp teacher heard the news and went to meet him. He walked 1.2 kilometers more per hour than Li Hua. Another 1.5 hours later, Zhang Ming rode his bike from school to the camp to report to the camp, but the three met somewhere on the way. Ask the cyclist how many kilometers per hour.
李华从学校出发，以每小时4千米的速度步行到20.4千米外的冬令营报到．半小时后，营地老师闻讯前往迎接，每小时比李华多走1.2千米．又过了1.5小时，张明从学校骑车去营地报到，结果三人在途中某地相遇．问骑车人每小时行多少千米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 + (1/2)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 * (1/2)</gadget>
<output>2</output>

<gadget id="calculator">20.4 - 2</gadget>
<output>18.4</output>

<gadget id="calculator">4 + 4 + 1.2</gadget>
<output>9.2</output>

<gadget id="calculator">18.4 / 9.2</gadget>
<output>2</output>

<gadget id="calculator">2 - 1.5</gadget>
<output>0.5</output>

<gadget id="calculator">(5/2) / 0.5</gadget>
<output>5</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>