Two cars depart from the east and west stations at the same time. The first time we met at a place 60 kilometers away from East Railway Station. After that, the two cars continued to move forward at the original speed. After arriving at each other's station, they return immediately and meet again 30 kilometers west of the midpoint. How many kilometers are the two stations apart?
两辆汽车同时从东、西两站相向开出．第一次在离东站60千米的地方相遇．之后，两车继续以原来的速度前进．各自到达对方车站后都立即返回，又在距中点西侧30千米处相遇．两站相距多少千米？
<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<gadget id="calculator">60 + 120 + 30</gadget>
<output>210</output>

<gadget id="calculator">210 / 1.5</gadget>
<output>140</output>

<result>140</result>