OG question

[nitinmenon89]

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930

[GMATGuruNY]

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930

The premise is about a very limited SAMPLING: hotels that the guidebook writer has visited.
The conclusion is about the WHOLE: all hotels built before 1930.

The writer assumes that what is true for the SAMPLING is true for the WHOLE.
To weaken the conclusion, the correct answer choice will show that sampling ≠ whole.

Answer choice D: The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Implication:
The country's poorly constructed hotels have probably been demolished.
Clearly, the guidebook writer could not have visited these hotels.
Thus, the sampling (the hotels that the writer has visited) ≠ the whole (all hotels built before 1930).

The correct answer is D.

[nikhilgmat31]

Answer is D


However if statement C is little reversed, it can give tight competition to D.
If C says
The materials available to carpenters working before 1930 were significantly better in quality from the materials available to carpenters working after 1930.

Then Answer would be C

[kalika991]

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930

The premise is about a very limited SAMPLING: hotels that the guidebook writer has visited.
The conclusion is about the WHOLE: all hotels built before 1930.

The writer assumes that what is true for the SAMPLING is true for the WHOLE.
To weaken the conclusion, the correct answer choice will show that sampling ≠ whole.

Answer choice D: The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Implication:
The country's poorly constructed hotels have probably been demolished.
Clearly, the guidebook writer could not have visited these hotels.
Thus, the sampling (the hotels that the writer has visited) ≠ the whole (all hotels built before 1930).

The correct answer is D.

I still fail to understand why the answer is D??
the paragrapgh says that "the quality of the original carpentry work is generally superior" for hotels built before 1930, which nowhere means that the carpentry in hotels build after 1930 were of poor quality, then how is option D valid??

[nikhilgmat31]

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930

The premise is about a very limited SAMPLING: hotels that the guidebook writer has visited.
The conclusion is about the WHOLE: all hotels built before 1930.

The writer assumes that what is true for the SAMPLING is true for the WHOLE.
To weaken the conclusion, the correct answer choice will show that sampling ≠ whole.

Answer choice D: The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Implication:
The country's poorly constructed hotels have probably been demolished.
Clearly, the guidebook writer could not have visited these hotels.
Thus, the sampling (the hotels that the writer has visited) ≠ the whole (all hotels built before 1930).

The correct answer is D.

Hi Mitch,

I agree with answer as D, But Option E is equally good as it says the training period of carpenters has been reduced since 1930.

[GMATGuruNY]

I still fail to understand why the answer is D??
the paragrapgh says that "the quality of the original carpentry work is generally superior" for hotels built before 1930, which nowhere means that the carpentry in hotels build after 1930 were of poor quality, then how is option D valid??

The author bases his conclusion on hotels that he has VISITED.
Answer choice D indicates that poorly constructed buildings are typically TORN DOWN.
Implication:
Most of the pre-1930 hotels that were poorly constructed have been torn down, WEAKENING the author's conclusion that carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

[GMATGuruNY]

Option E is equally good as it says the training period of carpenters has been reduced since 1930.

If anything, a longer apprenticeship for pre-1930 carpenters STRENGTHENS the conclusion that carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Since the correct answer choice must WEAKEN the conclusion, eliminate E.

[nikhilgmat31]

Option E is equally good as it says the training period of carpenters has been reduced since 1930.

If anything, a longer apprenticeship for pre-1930 carpenters STRENGTHENS the conclusion that carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Since the correct answer choice must WEAKEN the conclusion, eliminate E.

OK , my mistake. I got confused .

[anant03]

I still fail to understand why the answer is D??
the paragrapgh says that "the quality of the original carpentry work is generally superior" for hotels built before 1930, which nowhere means that the carpentry in hotels build after 1930 were of poor quality, then how is option D valid??

The author bases his conclusion on hotels that he has VISITED.
Answer choice D indicates that poorly constructed buildings are typically TORN DOWN.
Implication:
Most of the pre-1930 hotels that were poorly constructed have been torn down, WEAKENING the author's conclusion that carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Hi Mitch ,

Everything is clear , but option D doesn't indicate after 1930. We have to find something, which indicates about after 1930.

Please advise and correct me if am wrong.

[RBBmba@2014]

Hi GMATGuruNY,
In your above post you've mentioned that the Implication of the OA is "The country's poorly constructed hotels have probably been demolished."

Now if I construe that the option D actually STRENGTHENS the argument (hence its conclusion) as,I guess, D could also mean that hotels built before 1930 still EXIST because they're of better quality of original carpentry work and it makes them strong enough to sustain in spite of being older than post-1930 hotels, then how it'll be wrong ?

Could you please help ?

P.S: Other Verbal Experts - KINDLY feel free to shed light as well on this aspect/on my above interpretation!

[GMATGuruNY]

D could also mean that hotels built before 1930 still EXIST because they're of better quality of original carpentry work.

But what about pre-1930 hotels that do NOT still exist?
According to the OA, any pre-1930 hotels NOT still in existence were probably NOT well-built, WEAKENING the conclusion that carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

The OA points out the flaw in the writer's reasoning:
The writer cites information about a SAMPLING (pre-1930 hotels still in existence) to render a conclusion about the WHOLE (all pre-1930 hotels) -- a clear change in scope.

[GMATGuruNY]

Hi GMATGuruNY,
In your above post you've mentioned that the Implication of the OA is "The country's poorly constructed hotels have probably been demolished."

Now if I construe that the option D actually STRENGTHENS the argument (hence its conclusion) as,I guess, D could also mean that hotels built before 1930 still EXIST because they're of better quality of original carpentry work and it makes them strong enough to sustain in spite of being older than post-1930 hotels, then how it'll be wrong ?

An important take-away:
You are attempting to use the information in the OA to strengthen a PREMISE (that the pre-1930 hotels that the writer visited are well-built).
A premise is a FACT.
It CANNOT be strengthened.

[RBBmba@2014]

Hi GMATGuruNY,
In your above post you've mentioned that the Implication of the OA is "The country's poorly constructed hotels have probably been demolished."

Now if I construe that the option D actually STRENGTHENS the argument (hence its conclusion) as,I guess, D could also mean that hotels built before 1930 still EXIST because they're of better quality of original carpentry work and it makes them strong enough to sustain in spite of being older than post-1930 hotels, then how it'll be wrong ?

An important take-away:
You are attempting to use the information in the OA to strengthen a PREMISE (that the pre-1930 hotels that the writer visited are well-built).
A premise is a FACT.
It CANNOT be strengthened.

Hi GMATGuruNY - I understand you explanations above...

However,NOT able to get it completely why it'd be INCORRECT to say that if better quality of building carpentry means lower probability of building demolition then it's clear(AT LEAST, MOST LIKELY) that carpenters of pre-1930 hotels were more skilled than the carpenters of post-1930 hotels (and that's why pre-1930 hotels STILL EXIST). Otherwise, how it'd be possible for pre-1930 hotels to be STILL in EXISTENCE!

Could you please help ?

Also, a quick BUT IMPORTANT clarification required on your above post -- So,when we say that a particular option STRENGTHENS/WEAKENS the ARGUMENT, we ESSENTIALLY means that the Option actually STRENGTHENS/WEAKENS the CONCLUSION of the ARGUMENT. Right ?

[GMATGuruNY]

However,NOT able to get it completely why it'd be INCORRECT to say that if better quality of building carpentry means lower probability of building demolition

Why are the pre-1930 hotels that the guidebook writer visited still standing?
Because of their superior construction.
This is how you are attempting to interpret D.
But the conclusion is not about the hotels that the writer VISITED.
The conclusion is about ALL carpenters who worked on pre-1930 hotels.
It is possible that THOUSANDS of pre-1930 hotels have been torn down because of poor carpentry.
To strengthen the conclusion that pre-1930 hotel carpenters worked with more skill than post-1930 hotel carpenters, D would have to show that very few pre-1930 hotels have been demolished because of poor carpentry.

Also, a quick BUT IMPORTANT clarification required on your above post -- So,when we say that a particular option STRENGTHENS/WEAKENS the ARGUMENT, we ESSENTIALLY means that the Option actually STRENGTHENS/WEAKENS the CONCLUSION of the ARGUMENT. Right ?

Correct.
Any answer choice that attempts to strengthen or weaken a premise is WRONG.
A premise is a FACT: it cannot be strengthened or weakened.
The correct answer choice must strengthen or weaken the CONCLUSION.

[RBBmba@2014]

Why are the pre-1930 hotels that the guidebook writer visited still standing?
Because of their superior construction.
This is how you are attempting to interpret D.
But the conclusion is not about the hotels that the writer VISITED.
The conclusion is about ALL carpenters who worked on pre-1930 hotels.

OK. So, in the conclusion as it's NOT EXPLCITLY mentioned that writer is ONLY talking about hotels that he/she visited, we'd have to CONSIDER ALL pre-1930 hotels IN GENERAL. Right ?

And,GENERALLY, ( in any CR questions) if there is NO EXPLICIT information of any SPECIFICS like above, then we should ALWAYS consider that particular stuff as a whole IN GENERAL. Correct me please if wrong!