A bucket of water, after pouring out 40%, poured out 12 liters, poured out a total of 30 liters, how many liters is this bucket of water?
一桶水，倒出40%后又倒出12升，共倒出30升，这桶水有多少升．
<gadget id="calculator">30 - 12</gadget>
<output>18</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">18 / (2/5)</gadget>
<output>45</output>

<result>45</result>