A barrel of gasoline, 20% was used up for the first time, and the remaining 40% was used up for the second time, leaving 12 liters. How many liters does this barrel of gasoline weigh?
一桶汽油，第一次用去了20%，第二次用去了余下的40%，还剩下12升．这桶汽油共重多少升？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">12 / (3/5) / (4/5)</gadget>
<output>25</output>

<result>25</result>