I.   For the following derivations, state which rules were used to
            derive each line, and which lines they were derived from.

           A.   Derive S from

               1.   P v Q                   Premiss
               2.   P -> S                  Premiss
               3.   Q -> T                  Premiss
               4.   ~T                      Premiss
               5.   ~Q
               6.   P
               7.   S

           B.   Derive (~Q v ~T) from

               1.   P                       Premiss
               2.   P -> (~Z v ~F)          Premiss
               3.   Q -> Z                  Premiss
               4.   G -> F                  Premiss
               5.   T -> G                  Premiss
               6.   ~Z v ~F
               7.   T -> F
               8.   (Q -> Z) & (T -> F)
               9.   ~Q v ~T

          II.   Write formal derivations for the following arguments:

           A.   Derive P from

               1.   P v Q                   Premiss
               2.   Q -> R                  Premiss
               3.   ~R & S                  Premiss

           B.   Derive (Q v S) from

               1.   P -> R                  Premiss
               2.   R -> Q                  Premiss
               3.   P v T                   Premiss
               4.   (P v T) -> (T -> S)     Premiss