A refrigerator factory produced 3,600 refrigerators last month, an increase of 400 compared to the plan. By what percentage?
某冰箱厂上月生产电冰箱3600台，比计划增产了400台，增产了百分之几？
<gadget id="calculator">3_600 - 400</gadget>
<output>3_200</output>

<gadget id="calculator">400 / 3_200</gadget>
<output>1/8 = around 0.125</output>

<result>1/8 = around 0.125</result>