Recently in City X, developers have stopped buying land, contractors have found themselves going without work for longer periods, and banks have issued fewer mortgages. There must be fewer new residents moving to City X than there were previously.

Which of the following indicates a flaw in the reasoning above?
A This year several housing blocks have gone on the market after being held up for months by legal red tape.
B The average size of a new home has increased significantly over the past several years.
C Re-sales of condominiums have increased over the past six months.
DThe cost of materials such as lumber and cement has decreased over the past year.
E Sales of other big-ticket items, such as automobiles and boats, has remained steady over the past year.
answer is A

>>> this is one of the questions from the tests. i am unable to understand the reasoning of this questions. can anyone pls explain...

we need the actual source of the question in order to answer it.

when you say 'the tests' you've got to tell us which tests! (gmatprep? official test? manhattangmat cat test?)

once you post a source, we'll be able to answer the question.

thanks.

This is a question from the manhattan practice tests. thanks!

Thanks. It's also useful if you can explain what you do get and what you don't get about a problem, so that we can address your needs very specifically (and so that we don't take the time to explain things you already understand - we have a lot of questions to answer every day!). Please try to do that in future.

Premises:
- developers aren't buying land
- contractors have less work
- banks aren't issuing as many mortgages

Conclusion: not as many people are moving into City X

Task: find a flaw. This should hinge on the gap between the premises and the conclusion. The premises we accept as true. The conclusion? Is that the ONLY reason why the premises could be occurring? Surely, there could be other reasons...

A) This says some housing was built but wasn't actually sold because there was some legal red tape. But now, all of a sudden, the legal issues have been worked out and all of these houses come on the market at once. That oversupply could explain why there's a bit of a lull in the building market - there are already a lot of houses sitting there waiting to be sold.

B) The argument concentrates on the numbers of homes built (or not built, actually), not the size of the homes.

C) This choice is a little problematic to me - I've emailed our curriculum director to suggest that we change the wording here, because although the explanation says that the argument concentrates on new homes, not existing structures, the argument does not say that explicitly.

D) If anything, if it's cheaper to build homes, you'd expect there to be more homes being built. But there aren't - the premises say that building has decreased. So there must be some alternate explanation for why the building has decreased... and the argument offers one such alternate explanation as its conclusion. Nothing in this choice specifically tears down that conclusion.

E) Out of scope - we have no data to tie auto or boat sales to home sales, nor how any of that would follow through to the conclusion stated here: that there are fewer new residents.

Thanks a lot i will keep that in mind while posting a question next time. Infact for this very question i was confused between answer A and C.
To be more specific , in questions of 'finding the weakness, finding the Flaw in the arguement', what should be checked for:

We take the premise always to be true, so the flaw that i am finding is always related to the conclusion or it is specific- related to specific questions only like ' weaken the arguement/conclusion'.

In general what should be the approach besides finding the premise and conclusion in finding the flaw??
Sorry if i sound confused!!

No problem! When asked to find a flaw in the reasoning, you specifically want to find a flaw that, when exposed, would end up weakening the conclusion. So it's important to identify the conclusion correctly or you might get the question wrong! Most of the time, the flaw will expose some kind of problematic logic gap or assumption that lies between the premises and the conclusion. The second most common way to do this is to introduce a new premise / piece of info that weakens the conclusion.

Eg:
My tennis team won the state championship last year. This year, all the same players are returning and we've all gotten better. Therefore, we will win again this year.

The first sentence is a "fact" premise - can't challenge that. The second sentence is a "claim" or wishy-washy premise. What precisely does is mean to say we've gotten better? The third sentence is the conclusion.

Between the premises and the conclusion, I'm assuming that all other relevant factors have NOT changed - another team hasn't gotten better, etc. So if I introduced the information that last year's second and third-place teams combined their best players into one new super-team this year... that's going to hurt my claim that we'll win again this year. That's tearing down an assumption I'm making.

I could also introduce a new piece of info: because we won last year, we were moved up into a higher ranked division this year, and it is a much more challenging division (think moving from Tier II to Tier I in college athletics). That would also tend to hurt my claim that we'll win again this year.

Make sense?

this is very helpful...thanks a lot

You're welcome!