The purchase price of a commodity is 500 yuan, if the merchant wants to make a profit of 20%, what should be the selling price.
一商品进价500元，若商家要盈利20%，则售价应定为多少．
<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">500 * (6/5)</gadget>
<output>600</output>

<result>600</result>