There is a batch of coal in the factory, and it is planned to burn 6 tons per day, which can last for 80 days. The actual daily saving is 20% compared with the original plan. How many days did this batch of coal actually burn?
工厂里有一批煤，计划每天烧6吨，可以烧80天．实际每天比原计划节约20%．这批煤实际烧了多少天？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">6 * (4/5)</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">80 / (24/5)</gadget>
<output>50/3 = around 16.666667</output>

<gadget id="calculator">6 * (50/3)</gadget>
<output>100</output>

<result>100</result>