A factory produces a batch of cement. The original plan is to produce 150 tons per day, and the task can be completed on time. In fact, the production was increased by 30 tons per day, and the task was completed in only 25 days. How many days was originally planned to complete the production task?
某厂生产一批水泥，原计划每天生产150吨，可以按时完成任务．实际每天增产30吨，结果只用25天就完成了任务．原计划完成生产任务需要多少天？
<gadget id="calculator">150 + 30</gadget>
<output>180</output>

<gadget id="calculator">180 * 25</gadget>
<output>4_500</output>

<gadget id="calculator">4_500 / 150</gadget>
<output>30</output>

<result>30</result>