A cylindrical vessel A with a height of 10 cm and a volume of 76 cubic centimeters is filled with water. A 30 cm long cylinder B is inserted vertically, and the bottom surfaces of the two cylinders are in contact. At this time, part of the water overflows. When the cylinder is taken out from A, the height of the water surface in A is 7 cm, find the volume of cylinder B.
一个高为10厘米，容积为76立方厘米的圆柱形甲容器里装满了水，现将一根长30厘米的乙圆柱垂直插入，两圆柱的底面接触，这时一部分水溢出，当把乙圆柱从甲中取出时，甲中的水面高度为7厘米，求乙圆柱的体积．
<gadget id="calculator">76 / 8</gadget>
<output>19/2 = around 9.5</output>

<gadget id="calculator">10 - 7</gadget>
<output>3</output>

<gadget id="calculator">(19/2) * 3</gadget>
<output>57/2 = around 28.5</output>

<gadget id="calculator">(57/2) / 10</gadget>
<output>57/20 = around 2.85</output>

<gadget id="calculator">(57/20) * 30</gadget>
<output>171/2 = around 85.5</output>

<result>171/2 = around 85.5</result>