Supply the missing premise that makes the conclusion follow logically:P: X → not AP: not X → DP: ?C: A → C

willettc June 18, 2016

3rd P

How do you know C - >D is a connection in the 3rd Premise?

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Mehran June 23, 2016

@willettc our conclusion here is:

A ==> C

From the premises we are given, we know the following if A is present:

A ==> not X ==> D

This chain was created using the contrapositive of P1 (A ==> not X) and P2 (not X ==> D).

So at this point we know:

A ==> D

But the conclusion is A ==> C so we would need to close this gap by connecting D to C.

So this would be the missing premise:

D ==> C
not C ==> not D

The chain now would be:

A ==> not X ==> D ==> C
not C ==> not D ==> X ==> not A

Hope this helps! For a more in-depth discussion of these concepts, please watch our lesson on Sufficient & Necessary conditions.

Ashley September 4, 2024

is this an example of a logic game , or a logical reasoning question ?

Emil-Kunkin September 5, 2024

This is a drill that is meant to mimic a sufficient assumption question, which is LR. Games are gone now so we (hopefully) never need to worry about them again!