The chemical fertilizer factory produces a kind of agricultural fertilizer. It originally planned to produce 120 tons of chemical fertilizer per week. It took 4 weeks to complete the task, but it was completed 1 week ahead of schedule. How many tons was actually produced per week?
化肥厂生产一种农用肥，原计划每周生产化肥120吨，需用4周完成任务，结果提前1周完成，实际每周生产多少吨？
<gadget id="calculator">120 * 4</gadget>
<output>480</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">480 / 3</gadget>
<output>160</output>

<result>160</result>