There are two cube containers A and B, the ratio of the bottom area is 2:5, the water depth of A container is 6 cm lower than the water depth of B container, and then the same amount of water is poured into the two containers, and the water depth of both containers is exactly 18 cm. What is the depth of water in container A?
甲、乙两个正方体容器，底面积的比为2：5，甲容器水深比乙容器水深低6厘米，再往两个容器注入同样多的水，恰好两个容器的水深都是18厘米，原来甲容器中的水深多少厘米？
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">6 / 3</gadget>
<output>2</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">18 - 10</gadget>
<output>8</output>

<result>8</result>