The original price of a shampoo in the shopping mall is 50 yuan, and now it is sold at a 20% discount. If you use a membership card, you can get another 10% discount. How much does it cost for Aunt Li to buy a bottle of this shampoo with her membership card?
商场一种洗发水原价50元，现在打八折销售，如果使用会员卡，可以再打九折．李阿姨用会员卡买一瓶这样的洗发水需要多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">50 * (4/5) * (9/10)</gadget>
<output>36</output>

<result>36</result>