There are 10 kilograms of oil in barrel A, and 5 kilograms of oil is poured from barrel B into barrel A. The two barrels contain the same amount of oil. Ask A and B how many kilograms of oil there are in the two barrels.
甲桶里原有10千克油，从乙桶里倒出5千克油倒入甲桶，两桶的油一样多，问甲乙两桶共有多少千克油．
<gadget id="calculator">10 + 5</gadget>
<output>15</output>

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

<result>30</result>