After the city heating plant adopts the new technology, it saves a total of 12.6 tons of coal in the first 3 days of a week, and saves an average of 3.5 tons of coal per day in the last 4 days. How many tons of coal is saved on average this week?
市供热厂采用新技术后，在一周内的前3天共节约用煤12.6吨，后4天平均每天节约用煤3.5吨，这一周平均每天节约用煤多少吨？
<gadget id="calculator">3.5 * 4</gadget>
<output>14</output>

<gadget id="calculator">12.6 + 14</gadget>
<output>26.6</output>

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

<gadget id="calculator">26.6 / 7</gadget>
<output>3.8</output>

<result>3.8</result>