A batch of parts, originally planned to make 80 parts per day, was completed in 30 days, but actually 600 parts were made in the first 5 days. According to this calculation, how many days will it take to complete this batch of parts? (proportional solution)
一批零件，原计划每天做80个，30天完成，实际前5天就做了600个，照这样计算，完成这批零件共用多少天？(比例解)
<gadget id="calculator">80 * 30</gadget>
<output>2_400</output>

<gadget id="calculator">600 / 5</gadget>
<output>120</output>

<gadget id="calculator">2_400 / 120</gadget>
<output>20</output>

<result>20</result>