Admission Tests GMAT Question Answer
A certain law firm has 28 lawyers and has offices in three states, X, Y, and Z. Every lawyer in the firm is either Scensed in all three states or is licensed in only one of the three states. If 10 lawyers are kensed in State X, 11 are licensed in State Y, and 13 are licensed in State Z, how many lawyers are licensed only in State Z ?