The factory accepts a batch of production tasks. If there are 350 units left after 10 days of production by the first workshop, 250 units will be overfulfilled after 15 days of production by the second workshop; it is known that the production efficiency of the second workshop is that of the first workshop of (4/5). How many parts are there in this batch of production tasks?
工厂接受了一批生产任务，如果由第一车间生产10天后还剩下350个没有生产，如果由第二车间生产15天后则超额完成250个；已知第二车间的生产效率是第一车间的(4/5)．问这批生产任务共有多少个零件？
<gadget id="calculator">350 + 250</gadget>
<output>600</output>

<gadget id="calculator">4 * 15</gadget>
<output>60</output>

<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<gadget id="calculator">60 - 50</gadget>
<output>10</output>

<gadget id="calculator">600 / 10</gadget>
<output>60</output>

<gadget id="calculator">5 * 60 * 10</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 + 350</gadget>
<output>3_350</output>

<result>3_350</result>