The cost is increased by 40%, and another 20% discount is applied, earning 300 yuan. What is the profit margin?
成本提高40%，再打8折，赚300元．利润率是多少？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(7/5) * (4/5)</gadget>
<output>28/25 = around 1.12</output>

<gadget id="calculator">(28/25) - 1</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">300 / (3/25)</gadget>
<output>2_500</output>

<gadget id="calculator">300 / 2_500</gadget>
<output>3/25 = around 0.12</output>

<result>3/25 = around 0.12</result>