If retail stores experience a decrease in revenues during this holiday

It can only be (C). A, D, and E all make the assumption that retail stores have experienced a decrease in revenue, but that is not a given piece of information - everything is IF there is a decrease in revenue. For B, you can't make that claim because there's another factor which could decrease revenues (attitudes about gift-giving have changed). You're left with C.

This question uses simple logic

Here we have the condition if A then B

If [prices have risen beyond the level most people can afford], then it must be that salaries have NOT kept pace with rising prices during the past year

Now if you apply negation to if A then B it becomes If Not B then Not A. (I learnt this in one of my deduction classes )
So the question stem says what happens in case of "Not B" [If salaries have kept pace with rising prices during the past year], see you dont have a not as the sentence in the question's last sentence had.

Then in this case the answer should be Not A. Which means Not [prices have risen beyond the level most people can afford]

Hence the answer has to be C.

C.

if salaries have kept pace with rising prices during the past year

=> prices have not risen beyond the level most people can afford.

Using If X then Y... if not X then not Y.

(A) Attitudes toward extravagant gift-giving have changed. This can be considered only when retail stores experience a decrease in revenues during this holiday season. There is no mention that it actually happens. This seems to be shell game answer.
(B) Retail stores will not experience a decrease in retail sales during this holiday season.Again it is assuming the same.
(C) Prices in retail stores have not risen beyond the level that most people can afford during this holiday season.
(D) Attitudes toward extravagant gift-giving have not changed, and stores will not experience a decrease in revenues during this holiday season.Same as A. We don't know whether the sales will reduce.
(E) Either attitudes toward extravagant gift-giving have changed or prices have risen beyond the level that most people can afford during this holiday season.This may happen only when revenues are reduced. The argument does not state any reason for it to happen.

Except option C..all other options are nicely manipulated, but all are wrong for simple reason - we really don't know revenues would reduce.

Straight C. If salaries have kept pace with prices, then, per the premise, we can confidently infer that prices will not be beyond the reach of the said consumers.

Cheers,
Dee alte Fritz.

In general, the Analytical Reasoning questions from the LSAT are slightly more challenging versions of the GMAT CR questions, and therefore make good practice for GMAT students who want to challenge themselves. This particular question relies a bit too heavily on formal logic --- that's fine for the LSAT, but GMAT students need not wrestle with this much formal logic.

This argument has the following formal design.
First sentence = If M, then N or P
Second sentence = If P, then not Q.

Here,
M = retail stores experience a decrease in revenues during this holiday season
N = attitudes toward extravagant gift-giving have changed
P = prices have risen beyond the level most people can afford
Q = salaries have kept pace with rising prices during the past year

The question stem tells us ---- assume Q. With this, we can use a variant of a classical argument type known as Modus Tollens.

MODUS TOLLENS: Given (If W, then Y) and (not Y), we can conclude (not W).

The argument gives us "If P, then not Q", and the question stem gives us Q, so according to Modus Tollens, we can conclude "not P" --- i.e. "Prices in retail stores have not risen beyond the level that most people can afford during this holiday season." This is precisely what (C) says.

Because we know nothing about the truth or falsehood of M, we can draw no conclusion about N. If we were given both "not P" and M, we could conclude N, but in the absence of information about M, we can conclude nothing about N.

Everything I have said here is well beyond what anyone needs to know for the GMAT. If love this stuff, then forget business school --- take the LSAT and become a lawyer. If you are set on the GMAT and business school, then the last thing you need to know is Modus Tollens.

Please let me know if anyone reading this has any questions.

Mike

If retail stores experience a decrease in revenues during this holiday season, then either attitudes toward extravagant gift-giving have changed or prices have risen beyond the level most people can afford. [If A then B or C]
If attitudes have changed, then we all have something to celebrate this season. [If B then D]
If prices have risen beyond the level most people can afford, then it must be that salaries have not kept pace with rising prices during the past year. [If C then E]

Assuming the premises above to be true, if salaries have kept pace with rising prices during the past year, which one of the following must be true?

Quote:

Point to note:
If C then E ; If not E then not C.
If salaries have kept pace with rising prices during the past year then prices have not risen beyond the level most people can afford

(A) Attitudes toward extravagant gift-giving have changed.
(B) Retail stores will not experience a decrease in retail sales during this holiday season.
(C) Prices in retail stores have not risen beyond the level that most people can afford during this holiday season.

(D) Attitudes toward extravagant gift-giving have not changed, and stores will not experience a decrease in revenues during this holiday season.
(E) Either attitudes toward extravagant gift-giving have changed or prices have risen beyond the level that most people can afford during this holiday season.
BTW any logical reason to strike out A ?

I believe, A is struck out as the question stem has an EITHER/OR situation and since salaries have kept pace with the rising prices - then clearly prices are changing not attitudes

Thanks,
aimtoteach
------------
Looking for Kudos

Since it is a must be true question with conditional statements, I will rather go straight to the correct option than eliminate the wrong ones!

If A then B ... The contra positive statement Not B then Not A must be true.

Last line of the argument is a conditional statement: if prices have risen...... Then salaries have not risen....
Contra positive -- if salaries have risen... Then prices have not risen

Thus, Option C

Kudos.. If it helps!!!

i don't quite agree with C cuz C is also in the condition that the sales decreases so there must be 2 variant that varies together

Answer is C
Also consider the fact that this argument is for future sale and talks conditional situation. So at this moment we know that salaries have kept pace with price rise and hence we can comment only on affordability and not on attitudes.

Kudos please, if it helped

Only the last premise given in the passage is required to select C. The other premises do not form a part of the argument, hence the 2 simultaneous variants you mentioned are also not relevant.

Hi
Let " retail stores experience a decrease in revenues during this holiday season" Be X
"attitudes toward extravagant gift-giving have changed" Be Y
"prices have risen beyond the level most people can afford " Be Z ..

So the Q becomes
If X then Y or Z. If Y then S and If Z then T..
Finally it is given NOT T..

So straight from " IF Z then T". If NOT T, then NOT Z..

Z is "prices have risen beyond the level most people can afford "
So NOT Z will be "prices have NOT risen beyond the level most people can afford "
This is given in choice C..
C

No you cannot make this assumption. You missed out on the "if X" part in your question.
Y (attitude change) or Z (price increase beyond the level people can afford) are the two alternatives IF X (decrease in revenues) happens.

It is perfectly possible that both Y and Z do not happen and consequently, X does not happen. The argument does not say for sure whether X has happened or not.

by the way, the negation of
if X --> Y OR Z IS NOT Y AND NOT Z --> NOT X. (the argument is not this - Y --> NOT Z/Z --> NOT Y).

A is incorrect because we cannot say with certainty whether attitudes have changed(Y). that is whether Z happens or not has no bearing on Y.

Hope this helps

the answer must be C however i have a doubt regarding option A can someone explain why we should not go with this as it is mentioned in stimulus that there are either attitude or rise in prices reason for the decline in revenue , or any other reason may cause to decline in revenue that it not mentioned ?
please explain

Let,
Z: retail stores experience a decrease in revenues during this holiday season
A: attitudes toward extravagant gift-giving have changed
B: prices have risen beyond the level most people can afford

X: we all have something to celebrate this season
Y: salaries have not kept pace with rising prices during the past year.

The passage states the following:
IF Z, THEN either A OR B.
IF A, THEN X
IF B, THEN Y

Given NOT X.

Now, as per basic logic rules.
IF A, THEN X
implies:
IF NOT X, THEN NOT A. Thus option C is correct.

Nothing can be inferred about B and Y when NOT X is given.

It is not given that Z happens. Thus you cannot say that NOT A also implies that B happens. Hence your argument is wrong.

If the question were as follows then option A could be the correct option:

If retail stores experience a decrease in revenues during this holiday season AND salaries have kept pace with rising prices during the past year, which one of the following must be true?

However the blue part is missing in the question. Thus A is wrong.

OFFICIAL EXPLANATION:

This problem is mostly obfuscation. All we need is the last sentence of the argument. To diagram the last sentence let “prices have risen beyond the level most people can afford” be symbolized as R, and let “it must be that salaries have not kept pace with rising prices during the past year” be symbolized as ~S. This yields

R—>~S

Now in the question we are told “salaries have kept pace with rising prices during the past year.” In other words, S. This negates the conclusion in the diagram above, prompting us to apply the contrapositive to the diagram, which yields ~R. In other words, prices have not risen beyond the level that most people can afford. The answer is (C).

Can someone explain why option A is incorrect?
We are given two sufficient conditions for the revenues to decline. If one the condition is not the case then wont we direct it to the other condition?
@veritaskarishma GMATNinja