The electric fan factory plans to produce 1,200 electric fans in 16 days. After 4 days of production, due to improved technology, the efficiency will increase by 20%. How many days will it take to complete the plan?
电风扇厂计划16天生产电扇1200台，生产4天后，由于改进技术，效率提高20%，完成计划还需多少天？
<gadget id="calculator">4 / 16</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(1/16) * (6/5)</gadget>
<output>3/40 = around 0.075</output>

<gadget id="calculator">(3/4) / (3/40)</gadget>
<output>10</output>

<result>10</result>