Question

At a certain temperature, this reaction establishes an equilibrium with the given equilibrium constant Kc.

3A + 2B -><- 4C kc=3.13x10^29

If at this temperature, 2.50 mol of A and 3.70 mol of B are placed in a 1.00L container, what are the concentrations of A, B, C at equilibrium?

I know the answer to B and C but system is keep telling me A is wrong

The answer I have is

[A]=0 <--- wrong

[B]=2.033 <--- correct

[C}=3.333 <---- correct

The explanations says " Note above that the final concentration of A is approximately 0M. We initially assumed that the reaction went to competion, however, though this assumption was made, C will still dissociate, or back-react, to produce A and B in order to reach equilibriym. Therefore, set up an ICE table to calculate the equilibrium values for each specis where the final concentration above are now the initial values in ICE table.

So I did try the ICE table and I got 2.50 for A but it is still wrong

Please help me find the correct A