The foundry needs to produce a batch of parts. If it casts 300 parts per day, it will take 10 days to complete the task; if it casts 350 parts per day, it will take 5 days to complete the task. Q: How many days will it take to complete the task on time?
铸造车间要生产一批零件，如果每天铸造300个，完成任务要延长10天；如果每天铸造350个，完成任务要延长5天．问：按时完成任务要用多少天？
<gadget id="calculator">300 * 10</gadget>
<output>3_000</output>

<gadget id="calculator">350 * 5</gadget>
<output>1_750</output>

<gadget id="calculator">3_000 - 1_750</gadget>
<output>1_250</output>

<gadget id="calculator">350 - 300</gadget>
<output>50</output>

<gadget id="calculator">1_250 / 50</gadget>
<output>25</output>

<result>25</result>