If Elvira Johnson agrees to testify against the defendant and the pros

I arrived at D using Conditional Reasoning.

From the argument,

EJ AND Prestigious firm ------> CC -----> Defendant chances weakened AND most likely Lengthy sentence

Contrapositive of this is

~Defendant chances weakened OR ~most likely Lengthy sentence ---> ~CC ---> ~EJ OR ~Prestigious firm

From the contrapositive, the only thing that can be false is "Charlie Chase will Cooperate with the defence."

If Elvira Johnson agrees to testify against the defendant and the prosecution is able to get a prestigious firm to take their case, then the defendant's chances will be greatly weakened, and he will most likely be given a lengthy sentence. But Charles Chase, a powerful witness for the defense, will only cooperate if Elvira Johnson testifies and a prestigious law firm takes the prosecution's case.

E.J. AGAINST defence + prestigious firm takes prosecution case --> defendant chance weakened --> lengthy sentence
E.J testify + prestigious firm ---> CC witneess ---> FOR defence.

In other words, CC will testify only if first statement holds true.

Under these circumstances, if the defendant's chances are NOT greatly weakened, then which of the following must be false?

Elvira Johnson testifies against the defendant. ---- WEAKENED
The defendant will get a lengthy sentence. ----- ??
A prestigious firm will take the prosecution's case. --- WEAKENED
Charles Chase will cooperate with the defense. ----- WEAKENED
Elvira Johnson might testify against the defendant. ----- WEAKENED

I am going with B. Can anyone tell me whats wrong with this...or tell me whats the OA.

Its a great problem!!



In all

I picked D.

My reasoning was this:
If the defendant's chances are NOT weakened then some or all of the following cases (without going into the answers as yet) must be true:
1. Elvira Johnson might not have testified
2. A prestigious firm has not been able to take up the case
3. Charles Chase may not have cooperated
4. The victim may not be given a long sentence

Now coming to answer choices:
A. Elvira Johnson testifies against the defendant --> We can't be sure. If this is so, then you can't definitively say the prosecution has been successful in finding a good law firm.
B. The defendant will get a lengthy sentence --> This is a consequence. If we picked this, we would be going beyond the scope of the argument to state that there is another element influencing the sentence. Therefore, wrong.
C. A prestigious firm will take the prosecution's case --> Again, you can't say whether this definitely false without ruling out the other two options
D. Charles Chase will cooperate with the defense --> This will be the tipping point in the case. If E.J. testified, if the prosecution succeeded in getting the right law firm, and if Charles Chase cooperated, then the defendant's chances are going to be greatly reduced.
E. Elvira Johnson might testify against the defendant --> This can be misleading, but ultimately would lead nowhere.

Highly doubt this is a GMAT Prep question...this has the smell, flavor and taste of an LSAT question...Plus the logic used in this type of question is tested frequently on the LSAT...But that said -- lately I keep hearing that GMAC's CR questions are stretching the limits and are no longer sticking to the standard assumption, weaken/strengthen, inference and flaw questions.

So they give out more resolve the paradox type questions and boldface?

This is purely subjective -- so take it with a big scoop of salt. These are observations I have gathered from some colleagues and friends who have taken the GMAT within the last year or so.

Yes -- definitely more Boldface questions -- especially if you are doing well. A couple of my friends took the test a few weeks back -- and both mentioned they hardly saw 2, 3 or 4 strengthen / weaken questions tops. And even those were questions with "all of the following except" constructions. One of them said she got at least a couple of "evaluate the plan" and "the author is most likely to agree with all of the following except" type of questions.

Another interesting observation -- One of them said he saw just one probability question and zero combination questions (Quant 48). The general feedback was that co-ordinate geometry, number properties -- especially prime number, consecutive numbers, even-odd and integer properties, functions, percents and exponents seem to hold "high-value".

Simply put, choice D is the only one that definitively rules out both of the circumstances that lead to the weakened case.

Seems about right. The question is getting into a lot of formal logic along with the idea of an “AND” statement as the sufficient condition.

Either a really high level question or more of an LSAT question.

The key is that BOTH of the events linked by the “AND” in the sufficient condition statement must occur for the necessary condition to occur.



Posted from my mobile device

OFFICIAL ANSWER :

Identify the Question Type:

The question provides a set of circumstances that will be used to support the answer chosen. That makes this an Inference question. However, unlike most Inference questions, this one asks for something that must be false, rather than something that must be true. And it also must be false taking into account the additional condition in the question stem: if the defendant's chances are not weakened.

Untangle the Stimulus:

The stimulus gives some causal relationships. If Elvira Johnson testifies and a prestigious firm takes the case for the prosecution, then the defendant's chances will be weakened. Furthermore, Charles Chase will only testify if Elvira does and a prestigious firm does.

Predict the Answer:

If Chase cooperates, Elvira must testify and a prestigious firm must take the prosecution's case — the last sentence states these are the only conditions under which Chase will cooperate. Combine that with the first sentence: these conditions will greatly weaken the defendant's chances. Therefore, if, as the stem mandates, the defendant's chances are not greatly weakened, then Chase must not cooperate.

Evaluate the Choices:

(D) matches the prediction and is correct. It must be false, because if Chase cooperates, the defendant’s case would be weakened.

(A) is not necessarily false. The defendant's chances are weakened if Elvira testifies and a prestigious firm takes the case. If the defendant's chances are not weakened, Elvira could still testify -- there just wouldn't be a prestigious firm on the case.

(B) might be tempting at first; However, this is about chances. If the defendant's chances are weakened, he'll "most likely" get a longer sentence. However, even if the chances are not weakened, there's still a chance of a long sentence. It may not be "most likely," but it can't be ruled out.

(C) is not necessarily false. The defendant's chances are weakened if Elvira testifies and a prestigious firm takes the case. If the defendant's chances are not weakened, a prestigious firm could have still taken the case -- it may just be that Elvira didn't testify.

(E) only talks of Elvira possibly testifying; this would need to be known for sure (along with other information) to know if the defendant's chances are weakened, so this is incorrect.

TAKEAWAY: The right answer here depended on an important aspect of cause and effect relationships. If a cause always leads to an effect, then knowing that the effect didn't happen means that the cause didn't happen either.

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.