The two masters and apprentices work together to process a batch of parts, and it takes 20 days for the apprentice to do it alone. Now the two masters and apprentices process at the same time, processing a total of 150 parts every day, and the master has completed 60% of the entire task. Find out how many parts there are in this batch.
师徒二人共同加工一批零件，徒弟单独做需要20天完成，现师徒二人同时加工，每天共加工零件150个，完成时师傅完成了全部任务的60%．求这批零件共有多少个．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">150 * (2/5) * 20</gadget>
<output>1_200</output>

<result>1_200</result>