CR

[guest]

Picked from a set of LSAT questions ( yes, I dared to :D)

Either Perry’s faction or Tucker’s faction, but not both, will win control of the government. If Perry’s faction wins, the nation will suffer economically. If Tucker’s faction wins, the nation will suffer militarily.
Given the statements in the passage, which one of the following statements must be true?
(A) It is possible, but not certain, that the nation will neither suffer economically nor suffer militarily.
(B) If the nation suffers economically, it is certain that Perry’s faction has won control of the government.
(C) It is certain that the nation will suffer either economically or militarily, and also certain that it will not suffer both.
(D) If the nation suffers militarily, it is possible, but not certain, that Tucker’s faction has won control of the government.
(E) If the nation suffers both economically and militarily, it is certain that neither Perry’s faction nor Tucker’s has won control of the government.

OA is D - but I picked E. Any takers for this?

[guest612]

it is supposed that one will result in the other. therefore, if a result occurs (whether it be economic or military suffering), it is supposed that the respective person associated with that result may have been elected. Thus, OA D.

however, A causes B but that does not mean B causes A. Thus answer choice B which looks appealing is not the best answer. That's my thinking. Please comment.

[Genie]

I chose D too.
Perry’s faction wins, the nation will suffer economically : Does not mean that it will NOT suffer militarily.
Tucker’s faction wins, the nation will suffer militarily : Does not mean it will NOT suffer economically.

(A) It is possible, but not certain, that the nation will neither suffer economically nor suffer militarily. It WILL suffer atleast 1 of the effects if not both.

(B) If the nation suffers economically, it is certain that Perry’s faction has won control of the government. : It may be Tucker's because nothing in the Q mentions that the two sufferings as mutually exclusive.

(C) It is certain that the nation will suffer either economically or militarily, and also certain that it will not suffer both. : NA

(D) If the nation suffers militarily, it is possible, but not certain, that Tucker’s faction has won control of the government. :Correct

(E) If the nation suffers both economically and militarily, it is certain that neither Perry’s faction nor Tucker’s has won control of the government. : In no CERTAIN terms is there a mention of 2 events happening together.

[RonPurewal]

it's VERY unlikely that you'll see a question like this one.
because it's not COMPLETELY impossible, though - you just might see such a question under "draw a conclusion" in cr, once in a really, really blue moon - i'll give you the lowdown:

when you have an if-then statement, say 'if P, then Q' (where P and Q are statements), then you DO know the following:
if you know P --> then you definitely know Q
if you know NOT Q --> then you definitely know NOT P

you DON'T know the following:
if you know Q --> then you DON'T necessarily know P
if you know NOT P --> then you DON'T necessarily know NOT P

if you think of these things with an easy, pedestrian statement such as "if i'm a movie star then i'm rich", they should be obvious.
if i have that statement, then movie star --> rich, and, also, NOT rich --> NOT movie star.
however, if i know someone is rich, that doesn't mean s/he is a movie star, and, if someone is not a movie star, then s/he might still be rich.

--

in this problem:
if we know PERRY WINS --> then SUFFER ECONOMICALLY
therefore
if NOT SUFFER ECONOMICALLY --> then PERRY DIDN'T WIN

if we know TUCKER WINS --> then SUFFER MILITARILY
therefore
if NOT SUFFER MILITARILY --> then TUCKER DIDN'T WIN
that is all.
we don't know ANYTHING else.

in particular, knowing that the nation suffers, either economically or militarily, doesn't lead to ANY further conclusions. therefore, in choice (e), nothing is certain apart from the things we're already told.

[tarakdutta]

it's VERY unlikely that you'll see a question like this one.
because it's not COMPLETELY impossible, though - you just might see such a question under "draw a conclusion" in cr, once in a really, really blue moon - i'll give you the lowdown:

when you have an if-then statement, say 'if P, then Q' (where P and Q are statements), then you DO know the following:
if you know P --> then you definitely know Q
if you know NOT Q --> then you definitely know NOT P

you DON'T know the following:
if you know Q --> then you DON'T necessarily know P
if you know NOT P --> then you DON'T necessarily know NOT P

if you think of these things with an easy, pedestrian statement such as "if i'm a movie star then i'm rich", they should be obvious.
if i have that statement, then movie star --> rich, and, also, NOT rich --> NOT movie star.
however, if i know someone is rich, that doesn't mean s/he is a movie star, and, if someone is not a movie star, then s/he might still be rich.

--

in this problem:
if we know PERRY WINS --> then SUFFER ECONOMICALLY
therefore
if NOT SUFFER ECONOMICALLY --> then PERRY DIDN'T WIN

if we know TUCKER WINS --> then SUFFER MILITARILY
therefore
if NOT SUFFER MILITARILY --> then TUCKER DIDN'T WIN
that is all.
we don't know ANYTHING else.

in particular, knowing that the nation suffers, either economically or militarily, doesn't lead to ANY further conclusions. therefore, in choice (e), nothing is certain apart from the things we're already told.

Dear Ron,

I am sorry if the question sounds silly. I failed to understand why C is incorrect.

This is what I understood.

Either P'sF will win and cause the nation to suffer economically or T'sF will win and cause the nation to suffer economically. Both cannot win and so the nation will not suffer both. In C, we have "It is certain that the nation will suffer either economically or militarily, and also certain that it will not suffer both" . This explains what the argument is trying to say? What am I missing here?Can you please help so that I don't make the mistake again.

Thanks a Lot
T

[RonPurewal]

you are mistaking 'If X then Y' for 'If not X then not Y'. that's a big mistake.

e.g.,
If you drink poison, then you will die.
--> if you do NOT drink poison, you certainly can't say that you WON'T die! you still might die, for a whole host of other reasons.

similarly, there is no reason to think that either of these kinds of suffering will NOT occur if one of the parties is NOT elected. they might just be things that happen no matter what.

[RonPurewal]

MORE IMPORTANTLY
as i mentioned above, studying this kind of question is at best a waste of your time for the GMAT. the GMAT does not test 'formal logic', because the GMAT is not a test for future lawyers.

at worst—and perhaps more likely—studying this kind of thing will make you worse at the GMAT.
this is exactly the kind of thinking you WILL NOT have to do on the gmat. so, if you train yourself to do it, you may well be training yourself NOT to focus on what actually WILL be tested.