The master and the apprentice make 147 parts in total. The master makes 18 parts per hour, and the apprentice makes 12 parts per hour. The master makes 27 parts first, and then the apprentice makes it alone.
师徒两人共做147个零件，师傅每小时做18个，徒弟每小时做12个，师傅先做27个后，再由徒弟单独做，徒弟几小时才能完成任务？
<gadget id="calculator">147 - 27</gadget>
<output>120</output>

<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<result>10</result>