In this problem, I'm trying to determine whether or not the reaction is going to proceed in the forward direction towards the formation of more B or in the reverse direction towards the formation of more A. What I need to know is, is the reaction at equilibrium and if not, how am I going to get to equilibrium? The way we do this is we calculate the value of the reaction quotient, which we call Q, and we do this in the same way that we calculate K. I take Q = concentration of my product, divided by concentration of my reactant. And that's to the second power because I have a 2 in my balanced equation there. I can plug in the values that I know. So 0.350 for my concentration of B and 0.250 for my concentration of A, which I need to square. And when I solve that, I end up with Q = 5.60. Now I can compare the value of Q and K, and so I see that Q is greater than K. And what this tells me is that the reaction will go to the left. So the reaction proceeds in the reverse direction to form more A because what I need to happen is Q is great than K. I need Q to decrease. So Q needs to decrease. And in order for that to happen, the concentration of B needs to decrease. And the concentration of A needs to increase. And when that happens, Q will begin to approach K until we get to the point where Q equals K.