There are two cylindrical containers A and B, the ratio of their bottom area is 5:4, the water depth of A container is 7 cm, and the water depth of B container is 3 cm, and the same amount of water is poured into the two containers until the water depth is equal, how many centimeters is the water depth at this time?
甲乙两个圆柱容器，它们底面积的比为5：4，甲容器水深7厘米，乙容器水深3厘米，再往两个容器中注入同样多的水，直到水深相等，这时水深多少厘米？
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">7 + 16</gadget>
<output>23</output>

<result>23</result>