Buy a batch of coal, plan to burn 16 tons per day, and burn for 20 days; actually save 20% per day than before, how many days can you burn? (answer with ratio)
买来一批煤，计划每天烧16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">16 * 20</gadget>
<output>320</output>

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

<gadget id="calculator">16 * (1/5)</gadget>
<output>16/5 = around 3.2</output>

<gadget id="calculator">16 - (16/5)</gadget>
<output>64/5 = around 12.8</output>

<gadget id="calculator">320 / (64/5)</gadget>
<output>25</output>

<result>25</result>