Buy a batch of coal and plan to burn (1/4) ton per day, which can be burned for 20 days; the actual saving is 20% per day, so how many days can it be burned? (answer with ratio)
买来一批煤，计划每天烧(1/4)吨，可烧20天；实际每天比原来节约20%，这样可以烧多少天？(用比例解答)
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) * 20</gadget>
<output>5</output>

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

<gadget id="calculator">(1/4) * (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/4) - (1/20)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 / (1/5)</gadget>
<output>25</output>

<result>25</result>