Li Xin transported a cart of cabbage to the vegetable market for sale, and sold half of it at 0.50 yuan per kilogram, and sold the rest at a 20% discount. This cart of cabbage was sold for a total of 180 yuan.
李鑫将一车白菜运到菜市场出售，以每千克0.50元卖出一半，剩下的打八折出售，这一车菜一共卖了180元，这车菜一共多少千克？
<gadget id="calculator">0.5 * 0.5</gadget>
<output>0.25</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">0.5 * (4/5) * 0.5</gadget>
<output>0.2</output>

<gadget id="calculator">0.25 + 0.2</gadget>
<output>0.45</output>

<gadget id="calculator">180 / 0.45</gadget>
<output>400</output>

<result>400</result>