We need the formula for the volume of a cone...........and of course I had to look this up.
And thus on immersion in water it displaces a mass of
And now we work out the mass of the glass used,
And since the cone displaces a greater mass of water than the mass of the cone, the beast should float, because there is a net buoyant force upwards in water or in citric acid.
I like this question, so I am stealing it for A2 physics...........