A train of passenger cars and a train of freight trains depart from cities A and B at the same time, travel towards each other, and meet each other after 4 hours. Passenger cars travel an average of 115 kilometers per hour, and trucks travel an average of 85 kilometers per hour. How many kilometers are there between A and B?
一列客车和一列货车同时从A、B两城开出，相向而行，经过4小时相遇．客车平均每小时行115千米，货车平均每小时行85千米．A、B两城相距多少千米？
<gadget id="calculator">115 + 85</gadget>
<output>200</output>

<gadget id="calculator">200 * 4</gadget>
<output>800</output>

<result>800</result>