Uncle Wang bought a batch of alcohol and put it in two buckets A and B, both of which were not full. Pour all the alcohol into barrel A, and barrel A can hold another 20 liters. It is known that the capacity of barrel A is three times that of barrel B. How many liters of alcohol did Uncle Wang buy back?
王叔叔买回一批酒精，放在甲乙两个桶里，两个桶都未装满，如果把甲桶酒精倒入乙桶，乙桶装满后，甲桶还剩10升，如果把乙桶酒精全部倒进甲桶，甲桶还能再装20升，已知甲桶的容量是乙桶的3倍，王叔叔一共买回多少升酒精？
<gadget id="calculator">10 + 20</gadget>
<output>30</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 + 10</gadget>
<output>25</output>

<result>25</result>