Aunt Liu bought 100 pairs of the same trousers, and the selling price was higher than the purchase price (1/5), and she made a profit of 500 yuan. How much was the price of each pair of these trousers when she bought them?
刘阿姨购进100条同样的裤子，卖出的价格比购进价贵(1/5)，结果赚了500元，这批裤子的购进时每条价格是多少元？
<gadget id="calculator">500 / 100</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 / (1/5)</gadget>
<output>25</output>

<result>25</result>