The rate at which a solid substance dissolves varies directly as the amount of undissolved solid present in the solvent and as the difference between the saturation concentration of the substance and the instantaneous concentration of the solution. Five grams of A are placed in 100 cc of solvent B. The solution when saturated will hold 10 grams of A. If 2 grams of A dissolves in 1 hour, how many grams of A will be in solution in 2 hours