East and West are 650 kilometers apart. Cars A and B drive opposite each other from east to west for 2.5 hours at the same time, and the distance between the two cars is still 400 kilometers. How many more hours will it take for the two cars to meet?
东西两地相距650千米．甲乙两车同时从东西两地相对开出2.5小时后，两车还相距400千米．两车还要再行多少小时才能相遇？
<gadget id="calculator">650 - 400</gadget>
<output>250</output>

<gadget id="calculator">250 / 2.5</gadget>
<output>100</output>

<gadget id="calculator">400 / 100</gadget>
<output>4</output>

<result>4</result>