The school shipped five truckloads of coal. The first three truckloads weighed 6.85 tons on average, and the last two truckloads weighed 13.2 tons. How many tons did the five truckloads of coal weigh on average?
学校运来五车煤，前三车平均每车重6.85吨，后2车共重13.2吨，这五车煤平均每车重多少吨？
<gadget id="calculator">3 * 6.85</gadget>
<output>20.55</output>

<gadget id="calculator">20.55 + 13.2</gadget>
<output>33.75</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">33.75 / 5</gadget>
<output>6.75</output>

<result>6.75</result>