Two cars, A and B, drive from Dezhou to Beijing successively at the same speed. At 8:20 in the morning, car A is still 180 kilometers away from Beijing, and car B is still 156 kilometers away from Beijing; at 10:30 in the morning, car A leaves Beijing The distance is three times that of car B from Beijing. At this time, how many kilometers away is car B from Beijing?
甲乙两辆汽车用同样的速度先后从德州开往北京，上午8：20时，甲车离北京还有180千米，乙车离北京还有156千米；上午10：30，甲车离北京的路程是乙车离北京路程的3倍．这时，乙车离北京还有多少千米？
<gadget id="calculator">180 - 156</gadget>
<output>24</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<result>12</result>