a look at a few of them...
2. A and B is the case if and only if B or C is the case. What must follow from this premise?
B --> set A, B
C --> set A, B
where these are the only ways you can get set A, B
If A, then B, and if B, then C.
B or C, or ~B, or ~A, and if A, then C.
If B, then C. Also, if B, then B.
If B, then A. Also, if C, then A.
i picked the right answer but i wasn't sure about it. the first three choices were obviously wrong though. my thoughts on this were that just because B or C exist doesn't necessarily mean that A does also, or that set A, B has arisen... we only really know that if we are seeing set A, B that we have B and/or C. in other words, i'm confused. maybe "is the case" is what's throwing me off.
5. If someone says, "I killed all of the Gormagians," when is it logically true?
It's logically true when all of the Gormagiaons are dead.
well, just because they're all dead doesn't mean our "someone" killed all of them...
It's logically true when I kill all of the Gormagians.
i didn't know if we were taking "I" as the "someone"? there's also a tense issue... the tense is implying that "I" haven't killed them all yet... (i picked this one because i didn't know what else to pick.)
It's logically true when Gormagians never existed.
if they never existed, then how could our "someone" have killed them all?
It's logically true when I kill the last Gormagian.
this one is very similar to the second option, and i'm not sure it's significantly different from that option. that probably should have tipped me off that neither it or the second option can be the answer...
anyway, i would have preferred "none of the above" for this one. obviously i don't understand what "logically true" means?
10. Both ~A and B is equivalent to which of the following statements?
i couldn't tell on this one. this would mean we can't have both ~A and ~B, which we don't. but i don't think this is close enough to be "equivalent"...
well, no. because we do have ~A.
no, because we have both.
i picked this one, but wasn't sure about it. it's true basically.
11. If flangle and flingle, then flingle, then flangle, also means...
flangle = A; flingle = B
If A & B, then B, then A, also means...
A & B
B and ~A
~B or ~A
i selected the first one, which was wrong. i guess this is supposed to be a sequence, and at the end of the sequence we are left with flangle (A)?
12. If X=Y, Y=Z, and X is the ancestor of Y, then...
X gave rise to Y, and Y is exactly the same as X.
X, Y, and Z are all their own ancestors.
X is ancestor to Z, but Z is not ancestor to Y.
Y is ancestor to Z and X, but not himself.
Y and Z are the only ancestors of each other.
i think i picked the second one. the last two are obviously wrong. i didn't like my choice and i have a problem with the first choice, or correct answer.
i was thinking of X as basically giving rise to its clone, Y (where this clone is a perfect copy, and therefore is
exactly the same as X (equal to X)). Z could be another clone X gave rise to, or it could be a clone Y gave rise to (in the same manner in which X gives rise to identical clones). so my issue with the first option is that although that could be true, i don't think it has
to be true.
15. Either ostriches eat engines or both ostriches eat engines and orangutans eat steering wheels if, and only if...
either Os eat Es
or both Os eat Es and Rs eat Ws
if, and only if...
Os eat Es.
Os eat Es and Ws.
Rs eat Ws and Os eat Es.
Rs eat what Os eat.
it's between the first option and the third (i selected the third). i think that mainly what this is, is that you can't have any of this if you don't have "Os eat Es." the causality of it falls apart without that. i guess?