A piece of clothing is sold at a 20% discount, which is 15 yuan cheaper. How much is the original price of this piece of clothing?
一件衣服打八折出售，便宜了15元，这件衣服的原价是多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / (1/5)</gadget>
<output>75</output>

<result>75</result>