The two bottles of mosquito repellent water are 500ml in total, 40% of the large bottle is used, 10% of the small bottle is used, and the remaining mosquito repellent water in the two bottles is the same. How many milliliters of the original mosquito repellent water is in the vial? (solution in two ways)
两瓶驱蚊水一共500毫升，大瓶用去40%，小瓶用去10%，两瓶中剩下的驱蚊水一样多．小瓶中原有驱蚊水多少毫升？(用两种方法解)
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">180 / (9/10)</gadget>
<output>200</output>

<result>200</result>