The total weight of the water in the two buckets is 28 kg. If the water in the bucket A is poured into the bucket B with 4 kg, the water in the two buckets will have the same weight. Ask how many kilograms the water in the bucket A weighs.
两个桶里的水共重28千克，若把甲桶里的水倒给乙桶4千克，则两个桶里的水就一样重了，问甲桶里的水原来重多少千克．
<gadget id="calculator">28 + 8</gadget>
<output>36</output>

<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<result>18</result>