The master and the apprentice make a batch of parts together. There are 880 parts in total, the master can complete 50 parts per hour, and the apprentice can complete 30 parts per hour. How many hours can the two masters and apprentices complete this batch of parts? (Use equations to solve.)
师徒两人一起做一批零件．一共有880个，师傅每小时可以完成50个零件，徒弟每小时可以完成30个零件．这批零件师徒两人几小时可以完成？(用方程解答．)
<gadget id="calculator">50 + 30</gadget>
<output>80</output>

<gadget id="calculator">880 / 80</gadget>
<output>11</output>

<result>11</result>