A 4.60 mol sample of solid A was placed in a sealed 1.00 L container and allowed to decompose into gaseous B and C. The concentration of B steadily increased until it reached 1.40 M, where it remained constant. A(s)↽−−⇀B(g)+C(g)

Then, the container volume was doubled and equilibrium was re‑established. How many moles of A remain?