The master and apprentice make 600 parts together, the master makes 60 parts every day, and the apprentice makes 40 parts every day. How many days can the two work together to complete the task?
师徒两人合做600个零件，师傅每天做60个，徒弟每天做40个，两人合作几天可以完成任务？
<gadget id="calculator">60 + 40</gadget>
<output>100</output>

<gadget id="calculator">600 / 100</gadget>
<output>6</output>

<result>6</result>