There are 8 grandmothers in the nursing home, with an average age of 80.5; there are 12 grandfathers, with an average age of 75. What is the average age of the elderly in the hospital?
敬老院里有8位老奶奶，平均年龄80.5岁；有12位老爷爷，平均年龄75岁．全院老人的平均年龄是多少岁？
<gadget id="calculator">80.5 * 8</gadget>
<output>644</output>

<gadget id="calculator">75 * 12</gadget>
<output>900</output>

<gadget id="calculator">644 + 900</gadget>
<output>1_544</output>

<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">1_544 / 20</gadget>
<output>386/5 = around 77.2</output>

<result>386/5 = around 77.2</result>