Two cars, A and B, start from stations A and B at the same time and drive towards each other. At a distance of 40 kilometers from station A, the two cars meet for the first time head-on. After two stations, A immediately returns along the original road, and the two vehicles meet for the second time at a distance of 20 kilometers from station B. Ask: How far is the distance between A and B? If the two vehicles continue to move forward, where will they meet for the third time?
A、B两辆汽车从甲、乙两站同时出发，相向而行，在距甲站40千米处两车第一次迎面相遇，相遇后两车继续前进(保持原速)各自到达乙、甲两站后，立即沿原路返回，在距乙站20千米处两车第二次迎面相遇，问：甲、乙两站相距多远？若两车继续前进，则在何处第三次迎面相遇？
<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<gadget id="calculator">120 - 20</gadget>
<output>100</output>

<result>100</result>