Question 592846: INSTRUCTIONS: Select the conclusion that follows in a single step from the given premises.
Given the following premises:
1. ~N v H
2. Q > ~(~N v H)
3. (~N v Q) • (H > Q)
A. Q v Q 1, 3, CD
B. ~Q 1, 2, MT
C. ~N > ~(~N v H) 2, 3, HS
D. Q > (N • ~H) 2, DM
E. H > Q 3, Simp
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! The answer is choice A since this is a valid use of the constructive dilemma property.
Choice B uses modus tollens in a correct way, but you have to use double negation to do it properly. So more than one step is used. So choice B is out
Choice C uses the hypothetical syllogism, but it's completely incorrect. So choice C is out.
Choice D uses De Morgan's Law, which is valid, but it skips a step by leaving out double negation again...so choice D is out.
Choice E is correct, but commutation must be used first. So choice E is out.
So again, the answer is choice A.
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