An engineering team erected wires, 12.2 kilometers per day in the first 3 days, and 50.9 kilometers in total in the next 4 days. How many kilometers per day on average?
一个工程队架电线，前3天每天架线12.2千米，后4天共架线50.9千米，平均每天架线多少千米？
<gadget id="calculator">12.2 * 3</gadget>
<output>36.6</output>

<gadget id="calculator">36.6 + 50.9</gadget>
<output>87.5</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">87.5 / 7</gadget>
<output>12.5</output>

<result>12.5</result>