Uncle Li processed a total of 75 machine parts from 10 am to 3 pm. How many machine parts are processed on average per hour?
李叔叔从上午10是工作到下午3时，一共加工了75个机器零件，平均每小时加工多少个机器零件？
<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">75 / 5</gadget>
<output>15</output>

<result>15</result>