A commodity, according to the current price, the profit is 20% of the cost, if the profit is to be increased to 30%, then the selling price should be increased ((())/(())).
一件商品，按现价，利润是成本的20%，若要把利润提高到30%，那么售价应提高((())/(()))．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">1 * (13/10)</gadget>
<output>13/10 = around 1.3</output>

<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 * (6/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(13/10) - (6/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) / (6/5)</gadget>
<output>1/12 = around 0.083333</output>

<result>1/12 = around 0.083333</result>