Question 1187346
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 1. (O ⊃ C ) ● (∼S ⊃ ∼D)
 2. (E ⊃ D) ● (∼E ⊃ ∼C )      / O ⊃ S

 3. O ⊃ C                  1, Simplification
 4. (∼S ⊃ ∼D) ● (O ⊃ C )  1, Commutation
 5. ∼S ⊃ ∼D               4, Simplification
 6. ~~D ⊃ ~~S              5, Transposition
 7. D ⊃ S                  6, Double negation
 8. E ⊃ D                  2, Simplification
 9. (∼E ⊃ ∼C) ● (E ⊃ D )  2, Commutation
10. ∼E ⊃ ∼C               9, Simplification
11. ~~C ⊃ ~~E             10, Transposition
13. C ⊃ E                 11, Double negation
14. O ⊃ E                 3,13, Hypothetical syllogism
15. O ⊃ D                 14,8, Hypothetical syllogism
16. O ⊃ S                 16,7, Hypothetical syllogism

Edwin</pre>