The distance between A and B is 380 kilometers. The bus and the truck drive from the two places respectively. After 3 hours, the distance is still 20 kilometers. The bus travels 70 kilometers per hour. How many kilometers per hour does the truck travel?
甲、乙两地相距380千米，客车和货车分别从两地相对开出，3小时后还相距20千米，客车每小时行驶70千米，货车每小时行多少千米？
<gadget id="calculator">70 * 3</gadget>
<output>210</output>

<gadget id="calculator">380 - 210 - 20</gadget>
<output>150</output>

<gadget id="calculator">150 / 3</gadget>
<output>50</output>

<result>50</result>