train travels from city A to city B at a speed of 80 kilometers per hour for 6 hours, at a speed of 90 kilometers per hour for 7 hours, and at a speed of 110 kilometers per hour for 3 hours. Find this The average speed of the train.
一列火车从甲城到乙城，以每小时80千米的速度行驶了6小时，以每小时90千米的速度行驶了7小时，以每小时110千米的速度行驶了3小时，求这列火车的平均速度．
<gadget id="calculator">80 * 6</gadget>
<output>480</output>

<gadget id="calculator">90 * 7</gadget>
<output>630</output>

<gadget id="calculator">110 * 3</gadget>
<output>330</output>

<gadget id="calculator">480 + 630 + 330</gadget>
<output>1_440</output>

<gadget id="calculator">6 + 7 + 3</gadget>
<output>16</output>

<gadget id="calculator">1_440 / 16</gadget>
<output>90</output>

<result>90</result>