The master makes 48 parts per hour, and the apprentice makes 36 parts per hour. If the master makes parts in 9 hours, how many hours does the apprentice make?
师傅每小时做48个零件，徒弟每小时做36个零件，师傅9小时做的零件，徒弟要做多少小时？
<gadget id="calculator">9 / 36</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">48 * (1/4)</gadget>
<output>12</output>

<result>12</result>