The two masters and apprentices process a batch of parts. It takes 15 hours for the master to do it alone, and the apprentice can process 60 pieces per hour. Now the master and the apprentice are processing at the same time. When the task is completed, the number of parts processed by the apprentice is the master's (4/5). How many parts are there in total?
师徒两人加工一批零件．由师傅单独做需要15小时，徒弟每小时能加工60个．现由师、徒两人同时加工，完成任务时，徒弟加工的个数是师傅的(4/5)，这批零件共有多少个？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">60 / (4/5)</gadget>
<output>75</output>

<gadget id="calculator">75 * 15</gadget>
<output>1_125</output>

<result>1_125</result>