factory produces a batch of parts. The original plan is to produce 900 parts per day, and the completion is completed in 40 days. The actual production is 1200 parts per day. According to this calculation, how many days can it be completed?
某工厂生产一批零件，原计划每天生产900个，40天完成，实际每天生产1200个．照这样计算，多少天能完成？
<gadget id="calculator">40 / 1_200</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">900 * (1/30)</gadget>
<output>30</output>

<result>30</result>