Two cars set off from cities A and B at the same time and drive in opposite directions. After 2.2 hours, the distance between the cars is 680 kilometers. Car A travels 80 kilometers per hour, and car B travels 85 kilometers per hour. How many kilometers are there between cities A and B?
两辆汽车同时从A、B两个城市出发，背向而行，2.2小时后辆车相距680千米．甲车每小时行80千米，乙车每小时行85千米，A、B两城相距多少千米？
<gadget id="calculator">80 + 85</gadget>
<output>165</output>

<gadget id="calculator">165 * 2.2</gadget>
<output>363</output>

<gadget id="calculator">680 - 363</gadget>
<output>317</output>

<result>317</result>