Two cars departed from the east and west stations at the same time. They met for the first time at 60 kilometers away from the east station. The two cars moved forward at the original speed. How many kilometers are the distance between the two stations?
两辆汽车同时从东、西两站相对开出，第一次在离东站60千米处相遇，两车又以原来的速度前进，各车到站后立即返回，又在离中点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>