There is a cylindrical beverage bottle. The volume is 750 ml. Now there is some juice in the bottle, the height of the juice in the bottle is 20 cm when it is upright, and the height of the empty part in the bottle is 5 cm when it is upside down. How many milliliters of juice is in the bottle?
有一种圆柱形的饮料瓶．容积是750毫升．现在瓶中装有一些果汁，正放时瓶内果汁高度是20厘米，倒放时瓶内空余部分的高度为5厘米．问瓶内装有果汁多少毫升？
<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">750 * (4/5)</gadget>
<output>600</output>

<result>600</result>