The distance between Nanjian and Kunming is 360 kilometers. The car starts from Nanjian to Kunming and travels 80 kilometers per hour. The truck travels from Kunming to Nanjian. The two vehicles meet after 3 hours. How many miles per hour does the truck travel?
南涧到昆明相距360千米，小汽车从南涧出发到昆明，每小时行驶80千米，货车从昆明到南涧，3小时后两车相遇．货车每小时行驶多少千米？
<gadget id="calculator">360 / 3</gadget>
<output>120</output>

<gadget id="calculator">120 - 80</gadget>
<output>40</output>

<result>40</result>