1. The problem statement, all variables and given/known data Identify the following as a valid or an invalid argument. p → q q ∧ r -------------- ∴ ~r → ~p 2. Relevant equations N/A 3. The attempt at a solution Truth table values: (a) p → q TTFFTTTT (b) q ∧ r TFFFTFFF (c) a ∧ b TFFFTFFF (d) ~r → ~p TFTFTTTT (e) c → d TTTTTTTT Since (e) is true in every case, the argument is valid. However, the answer in the back of the book says invalid. Am I doing something wrong, or is the answer in the book wrong?