A conical container with a height of 15 cm is filled with water, and then all the water is poured into a cylindrical container with the same height as its bottom. What is the height of the water surface in cm?
一个圆锥形容器，高15厘米，里面装满了水，然后把水全部倒入和它等底等高的圆柱形容器里，水面高多少厘米．
<result>5</result>