The master and the apprentice each process the same number of parts and process them at the same time. When the master completes the task, the apprentice still has 30 unfinished parts. When the apprentice completes the task, the master can overcomplete 50 parts. How many parts are there in total?
师徒两人各加工同样多的零件，同时加工，当师傅完成任务时，徒弟还有30个没有完成，当徒弟完成任务时，师傅可以超额完成50个，这批零件总数共多少个？
<gadget id="calculator">50 * 30</gadget>
<output>1_500</output>

<gadget id="calculator">50 - 1 - 30</gadget>
<output>19</output>

<gadget id="calculator">1 + 19</gadget>
<output>20</output>

<gadget id="calculator">1_500 / 20</gadget>
<output>75</output>

<result>75</result>