There are two barrels of oil, A and B. If 15 kilograms of oil is poured from barrel A into barrel B, the weight of the two barrels is equal. How many kilograms of oil is there in barrel A compared to barrel B?
有甲、乙两桶油，如果从甲桶油中倒出15千克装入乙桶，这时两桶油的重量相等，原来甲桶比乙桶多多少千克油？
<gadget id="calculator">15 + 15</gadget>
<output>30</output>

<result>30</result>