The cost of a commodity is 200 yuan, and it is priced at 30% of the profit. When it is sold, it will be sold at 10% of the price. How much profit can it still make?
一种商品的成本是200元，以盈利三成来定价，出售时将定价九折出售，仍能盈利多少．
<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">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">(13/10) * (9/10)</gadget>
<output>117/100 = around 1.17</output>

<gadget id="calculator">(117/100) - 1</gadget>
<output>17/100 = around 0.17</output>

<result>17/100 = around 0.17</result>