"Liquids A and B, which have identical molar volumes, are mixed together in equal volumes to form a 75 mL mixture. The liquids are partially miscible and the mixture phase separates into an upper phase with a composition xA=0.45 and a lower phase with a composition xA=0.82. How many milliliters of each phase forms? What will happen if another 25 mL of liquid B were added to the mixture?"

Question

"Liquids A and B, which have identical molar volumes, are mixed together in equal volumes to form a 75 mL mixture.  The liquids are partially miscible and the mixture phase separates into an upper phase with a composition xA=0.45 and a lower phase with a composition xA=0.82.  How many milliliters of each phase forms?  What will happen if another 25 mL of liquid B were added to the mixture?"
I know that I need to use the lever rule, and the V(total)=V(a)n(a)+V(b)n(b)
I am 100% convinced I am over thinking this, but are the n(a) the same as n(alpha) in the lever rule?