Electric Potential of charged isolated body.

1. The problem statement, all variables and given/known data
Two equal isolated metallic bodies A & B start with no charge and zero potential. A is given a charge giving B the potential U. B is then Grounded giving A the potential U.

What potential did A have before B was grounded?

Hint: Use symmetry and use potential coefficients.

2. Relevant equations
V2-V1=int(E,1,2)
V=1/(4*pi*eps) * int(e_density/R dl)

3. The attempt at a solution
Don't know where to start here. The answer includes only U as variable. I think it's a question about relations.

 

2V and 2U.

I should have stated that with no charge both potentials is zero.

I don't see your point. The anser is V_A = U (√ 5 +1)/2