The master and apprentice make a total of 279 parts, the master makes 16 parts every time, and the apprentice makes 14 parts every time. After the master has done 39, how many hours will the master-apprentice work together?
师徒两人共做279个零件，师傅每时做16个零件，徒弟每时做14个零件．师傅做了39个后，师徒合作还要做多少小时？
<gadget id="calculator">279 - 39</gadget>
<output>240</output>

<gadget id="calculator">16 + 14</gadget>
<output>30</output>

<gadget id="calculator">240 / 30</gadget>
<output>8</output>

<result>8</result>