One piece of business is priced at a profit of 20% of the cost. Now that the cost is reduced by 20% and the price remains the same, how much profit can you make by selling it?
一件商按成本的20%利润来定价，现在成本降低20%，定价不变，卖出可以获利百分之几？
<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 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(6/5) - (4/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / (4/5)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>