To produce a batch of chemical fertilizers, it is planned to produce 120 tons per day, and it takes 20 days to complete the task. As a result, the task is completed 4 days ahead of schedule. How many tons of chemical fertilizers are produced on average per day? (Solution with the knowledge of proportion))
要生产一批化肥，计划每天生产120吨，需要20天能完成任务，结果提前4天完成任务，平均每天生产化肥多少吨？(用比例的知识解))
<gadget id="calculator">120 * 20</gadget>
<output>2_400</output>

<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">2_400 / 16</gadget>
<output>150</output>

<result>150</result>