workshop processes a batch of parts. The original plan is to produce 4,000 parts per day, and the task can be completed in 20 days. Actually, 1,000 more pieces are processed every day than the original plan. How many days does it actually take to complete the task? (Solve with ratio)
一个车间加工一批零件，原计划每天生产4000个零件，20天可以完成任务．实际每天比原计划多加工1000个，实际需要多少天完成任务？(用比例解)
<gadget id="calculator">4_000 * 20</gadget>
<output>80_000</output>

<gadget id="calculator">4_000 + 1_000</gadget>
<output>5_000</output>

<gadget id="calculator">80_000 / 5_000</gadget>
<output>16</output>

<result>16</result>