Two cars A and B are traveling towards each other at the same time from stations A and B respectively. The first time we met was 40 kilometers away from Station A. The two cars continue to move forward at the original speed. After arriving at the station, the two cars return immediately and meet again at a place 20 kilometers away from station B. How many kilometers are the distance between the two stations.
甲、乙两辆汽车分别从甲、乙两站同时相向而行．第一次相遇在离甲站40千米的地方．两车仍以原速度继续前进，两车分别到站后立即返回，又在离乙站20千米的地方相遇．两站相距多少千米．
<gadget id="calculator">40 * 3</gadget>
<output>120</output>

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

<result>100</result>