A car drives from A to B at 60 kilometers per hour for 4 hours and exceeds 30 kilometers from the midpoint of the two places. Find the distance between A and B?
一辆汽车从甲地开往乙地，每小时行60千米，行了4小时，超过两地中点的30千米，求甲乙两地的距离？
<gadget id="calculator">60 * 4</gadget>
<output>240</output>

<gadget id="calculator">240 - 30</gadget>
<output>210</output>

<gadget id="calculator">210 * 2</gadget>
<output>420</output>

<result>420</result>