A coat costs 500 yuan, and mothers can enjoy a 15% discount with a VIP card. How much discount can mom buy this dress?
一件上衣500元，妈妈持贵宾卡可享受八五折优惠．妈妈买这件衣服，可以优惠多少元？
<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">500 * (3/20)</gadget>
<output>75</output>

<result>75</result>