279 Answers and Solutions to Selected Exercises (f) Denote “ Victor studies hard” by p, “ Victor is clever” by q , “ Victor will go to a university” by r, and “ Victor will get a good job” by s Then the inference rule on which the argument is based is: (p ∧ q ) → r, ¬p → ¬s q → (r ∨ ¬s) The rule is sound, hence the argument is correct (p ∧ q) → r : T , ¬p → ¬s : T , q → (r ∨ ¬s) : F q : T , r ∨ ¬s : F r : F , ¬s : F s:T ¬p : F ¬s : T p:T s:F × p∧q :F p:F × r:T × q:F × (h) Denote “ Johnnie learns logic” by p, “ Johnnie skips lectures” by q , and “ Johnnie passes the exam” by r