A product is 15 yuan cheaper than the original price after a 15% discount. What is the original price?
一件商品打八五折后比原价便宜15元，原价是多少元．
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 - (17/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">15 / (3/20)</gadget>
<output>100</output>

<result>100</result>