Master and apprentice work together to process a batch of parts. The ratio of work efficiency between master and apprentice is 3:2. The apprentice processes 30 parts per hour. How many parts does the master process per hour? (Solution by proportional method)
师徒共同加工一批零件，师傅和徒弟工作效率的比是3：2，徒弟每小时加工30个，师傅每小时加工多少个？(用比例方法解)
<gadget id="calculator">3 * 30</gadget>
<output>90</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<result>45</result>