In a charity sale, Wang Gang sold 400 cups of lemonade and hot chocolate, earning 546 yuan. If lemonade is 1 yuan per cup and hot chocolate is 2 yuan per cup, how many cups of lemonade did Wang Gang sell in this charity sale?
在一次义卖活动中，王刚卖柠檬水和热巧克力共400杯，得款546元．如果柠檬水1元/杯，热巧克力2元/杯，那么王刚在这次义卖活动中卖出了多少杯柠檬水．
<gadget id="calculator">400 * 2</gadget>
<output>800</output>

<gadget id="calculator">800 - 546</gadget>
<output>254</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">254 / 1</gadget>
<output>254</output>

<result>254</result>