After 60% of a barrel of oil is used up, another 12 liters are poured in. At this time, there is as much oil in the barrel as before. How many liters is this barrel of oil originally?
用去一桶油的60%后，又倒入12升，这时桶里的油和原来一样多．这桶油原来有多少升？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">12 / (3/5)</gadget>
<output>20</output>

<result>20</result>