Lucinda will soon be attending National University as an engineering

Yeah this is a nasty one.

This is based on the understanding of causal reasoning:

Lucinda is an engineering major at National University.
Most residents of Western Hall are engineering majors.
Conclusion: Lucinda will probably live in Western Hall.

The argument mistakenly assumes that what is true for "most" engineering major residents applies to one specific engineering major (Lucinda).

A: this is a tricky one. but if the statements are rearranged can be seen as a logical reasoning rather than flawed reasoning: cities with mall become regional hub. A mall being built in our city will lead us to become a regional hub
B: does not align with the structure that what is true for most is also true for one. it talks about growth over time which is not our scope of reasoning
C: talks about cities having excellent transportation than pivot to cities not having excellent transportation does not align with the structure. This is more of a conditional reasoning statement
D: its a reversal it talks about what is true of one will be true for all
E: this mirrors the logic in the passage what is true of 'most cities' will be true for our city. most cities are regional hub (contain mall is additional info about regional hub). we are getting mall so we will become regional hub. suggests that mall is essential for becoming regional hub whereas the 1st statement only meant the regional hubs contain mall.

But the option said that most cities with a mall are a regional hub not will become a regional hub .. so why A is different than E?

A is not reasoning in the wrong direction, so it doesn't share the original flaw the way E does. A would be like saying "Lucinda will be an engineering major. Most engineering majors live in Western Hall. So Lucinda will probably live in Western Hall." There's not much wrong with that argument. It just assumes that she will probably do what most other engineers do. Since it's a probabilistic prediction, that's not too far out.

E, on the other hand, commits the same mistaken reversal as the original argument. Just as the original treats "Most in WH are EM" as "Most EM are in WH," answer E treats "Most hubs contain malls" as "Most cities with malls are hubs." The are/will become distinction doesn't matter, since the logic is the same either way. Sure, if most cities with malls are hubs, that doesn't mean that building a mall will MAKE the city into a hub, just as the statement "Most senators are men" doesn't mean that if a woman becomes a senator, she will become a man. However, if we had that version, the argument in E wouldn't have the flaw of the original. It would be saying "Most cities with malls are hubs, so if we build a mall, we'll be a hub." That would at least be reasoning in the right order, from "We have X" to "Most X are Y" to "We have Y." But the original and A get that flipped. They go from "We have X" to "Most Y are X" to "We have Y." That's a different and less logical path.

Here's another version:
My cousin lives in a big city. (My cousin is X)
Most criminals live in big cities. (Most Y are X)
So my cousin is probably a criminal. (My cousin is probably Y)

Wait. Just because most criminals live in big cities, does that really mean most people in big cities are criminals? Surely the logic doesn't run in both directions! This is what original/E are doing.
If we flip the order of either of the second statement, though, we'd have a much more reasonable argument, like A.

My cousin lives in a big city. (My cousin is X)
Most people who live in big cities are criminals. (Most X are Y)
So my cousin is probably a criminal. (My cousin is probably Y)

Notice how the statements line up?
Cousin --> city --> criminal
Answer choice A: City --> mall --> hub

We could also get the same thing by swapping the original premise and conclusion:
My cousin is a criminal.
Most criminals live in big cities.
So my cousin probably lives in a big city.
Cousin --> criminal --> city

By the way, if this isn't your favorite kind of reasoning, keep in mind that this is LSAT material, and you are unlikely to be asked to do anything like this on the GMAT. It's nice to be able to spot a logical reversal when you encounter one (are most city dwellers really criminals?? no!), but you're not likely to have to identify a parallel argument like this, nor are you likely to see a lot of reasoning based on quantifiers (most X are Y, most Y are Z, etc.).

Lucinda will soon be attending National University as an engineering major. At National University, most residents of Western Hall are engineering majors. Therefore, Lucinda will probably live in Western Hall.

Lets visualize this argument -
L will attend NU as an Engg. major
There is a WH (there may be NH, SH, EH) and 51% or more of residents of WH are Engg. major
So, L is part of WH (why because 51 out of 100 are engg. major, 49 out of 100 may be non-engg. major as well)

Which one of the following arguments exhibits a flawed pattern of reasoning most similar to that exhibited by the argument above?

(A) A major shopping mall (MSM) is now being constructed in our city. Most cities with major shopping malls are regional economic hubs (REH). Therefore, our city will probably become a regional economic hub.

MSM in our city
Its saying that say there are 10 cities with MSM, and 6 out of 10 cities with MSM are REH. Meaning 4 cities with MSM are not REH.
So our city will become REH.

The main issue in this is 6 out of 10 also have MSM and they are REH
The remaining 4 also have MSM but not REH.
So how can we say our city with MSM will be part of REH. Basically 100% of cities in this cases are with MSM. The argument flawed pattern is very different. In the argument only 51% or more (it can be 100% as well but there is a difference between ALL and Most, isn't it?) are engg. majors, rest 49% or less can be non-engg. major.


(B) Cities that are regional economic hubs generally experience tremendous economic growth at some point. Our city is a regional economic hub that has never experienced tremendous economic growth. Thus it will probably experience tremendous economic growth in the future. - Irrelevant

(C) Cities that are regional economic hubs always have excellent transportation systems. It is widely agreed that our city’s transportation system is inadequate. Therefore, our city will probably never become a regional economic hub. - Irrelevant

(D) A major shopping mall was built in our city ten years ago, and our city has experienced tremendous economic growth since then. Therefore, most cities in which major shopping malls are built will experience tremendous economic growth shortly afterward. - Irrelevant

(E) Most cities that are regional economic hubs contain major shopping malls. A major shopping mall is now being constructed in our city. Therefore, our city will probably become a regional economic hub.

Say there are 10 cities with REH (equivalent to WH), so 6 out these 10 have MSM (most are engg. majors), and 4 out these 10 don't have MSM (similar to what argument says 49% are not engineering majors).
Our city has MSM (equivalent to Lucinda is an engg. major)
So our city will probably be REH (similar to argument: Lucinda will reside in WH)