Three people, A, B, and C, go from East Village to West Village at the same time. A rides a bicycle 12 kilometers faster than B and 15 kilometers faster than C. A travels 3.5 hours to the West Village and returns immediately, and meets B at a distance of 30 kilometers from the West Village. , Ask: How long has it been since C met A?
甲乙丙三人同时从东村去西村，甲骑自行车每小时比乙快12千米，比丙快15千米，甲行3.5小时到达西村后立刻返回，在距西村30千米处和乙相遇，问：丙行了多长时间和甲相遇？
<gadget id="calculator">2 / 12</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">30 * (1/6)</gadget>
<output>5</output>

<gadget id="calculator">5 - 3.5</gadget>
<output>1.5</output>

<gadget id="calculator">30 / 1.5</gadget>
<output>20</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<gadget id="calculator">5 + 20</gadget>
<output>25</output>

<gadget id="calculator">2 / 25</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">20 * 3.5 * (2/25)</gadget>
<output>5.6</output>

<result>5.6</result>