A truck and a bus start from places A and B, which are 400 kilometers apart, and meet each other in 5 hours. The bus travels 30 kilometers per hour. How many kilometers does the truck travel per hour? (equation solution)
货车和客车从相距400千米的甲乙两地相对开出，5小时相遇，客车每小时行30千米，货车每小时行多少千米？(方程解)
<gadget id="calculator">400 / 5</gadget>
<output>80</output>

<gadget id="calculator">80 - 30</gadget>
<output>50</output>

<result>50</result>