Chemical Equilibrium

Kc for the following reaction is 99.0
A2(g)

T(K)

⇌

B2(g)
In a one litre flask, 2 moles of A2 was heated to T(K) and the above equilibrium is reached. The concentrations at equilibrium of A2 and B2 are C1(A2) and C2(B2) respectively. Now, one mole of A2 was added to flask and heated to T(K) to establish the equilibrium again. The concentrations of A2 and B2 are C3(A2) and C4(B2) respectively. What is the value of C3(A2) in mol−1 ?