A and B go to Beijing from Songcun at the same time. After 2 hours, A is 12 kilometers ahead of B. At this time, A returns to Songcun due to some business, and meets B after walking for 30 minutes. After A arrives in Songcun, he immediately chases after B, and ends up in Beijing at the same time. How many kilometers is the distance between Songcun and Beijing?
甲、乙两人从宋村同时去北京，出发2小时后甲在乙前方12千米处，此时甲因事又重返宋村，行30分钟和乙相遇．甲到宋村后立即追乙，结果同时到北京．宋村与北京相距多少千米？
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">0.5 * 6</gadget>
<output>3</output>

<gadget id="calculator">12 - 3</gadget>
<output>9</output>

<gadget id="calculator">9 / 0.5 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 + 6</gadget>
<output>15</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">15 * 9 * 2 * (1/3)</gadget>
<output>90</output>

<result>90</result>