(∼G ∨ E) • (R ∨ M)
A) MT-valid.
B) Invalid.
C) DA-invalid.
D) MP-valid.
E) AC-invalid.

Question

(∼G ∨ E) • (R ∨ M) 
A) MT-valid. 
B) Invalid. 
C) DA-invalid. 
D) MP-valid. 
E) AC-invalid.

Quizplus · Accepted Answer

The statement is invalid. Since both (∼G ∨ E) and (R ∨ M) are disjunctions, at least one of them has to be true for the whole statement to be true. However, it is possible for both (∼G ∨ E) and (R ∨ M) to be false (for example, if G and R are true but E and M are false). Therefore, the statement is not logically valid.