Two trains depart from places A and B opposite each other, and meet at a distance of 120 kilometers from the midpoint after 3 hours. The fast train travels 200 kilometers per hour, how many kilometers per hour does the slow train travel?
两列火车从甲、乙两地相对开出，3小时后在距离中点120千米处相遇，快车每小时行200千米，慢车每小时行多少千米？
<gadget id="calculator">200 * 3</gadget>
<output>600</output>

<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<gadget id="calculator">600 - 240</gadget>
<output>360</output>

<gadget id="calculator">360 / 3</gadget>
<output>120</output>

<result>120</result>