Aunt Zhang from the landscaping office sprayed 820 apple trees with syrup from 10:00 a.m. to 3:00 p.m. How many apple trees does she spray on average per hour?
园林绿化所的张阿姨上午10时到下午3时，共给820棵苹果树喷了药水，她平均每小时喷多少棵？
<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">820 / 5</gadget>
<output>164</output>

<result>164</result>