#18 - Some planning committee members--those representing

[eober]

Hi,

Would you be able to provide explanation to question 18? How should I approach this question? Should I draw the conditionality? If so, how can I do that when it uses words such as "some" and "most"?

Thanks!

[David Boyle]

Hi,

Would you be able to provide explanation to question 18? How should I approach this question? Should I draw the conditionality? If so, how can I do that when it uses words such as "some" and "most"?

Thanks!

Hello eober,

There seems to be no "most" in question 18, though there are some "somes". "Some" means one or more, so you can diagram conditionality something like this:


PC (planning committee members)

some
-------> FI (financial interests)


PC ----> slash LS (live suburbs)


So if PC, then some FI, and no LS. There is an overlap, in that any PC with FI are also no LS, since every PC is no LS. Thus, answer E, "Some persons with significant financial interests in the planning committee's decisions do not live in the suburbs", is correct.
(For more info on "some", "most", etc., check out the "Formal Logic" section in Lesson 8 supplemental materials in the Student Center online.)

Hope this helps,
David

[Sherry001]

Hello and happy holidays !
I am so obsessed with this question that I sneaked away from my Christmas party just to write a question about this !
I have been working on this for a few days and it's bugging me. Could you please see where I am going wrong with my reasoning ? Particularly - I have an issue getting rid of D.


Planning committee members <SOME > Financial interest
Planning committee members --> do not work in suburbs
Planning committee members <SOME> Work in suburbs

A) WRONG : (financial -> are in the construction industry ) this is making an all statement about the some group .

B) WRONG : this is making an all statement about the some group again. We only know about some financial interes groups not working.

C) WRONG: this is overlapping the two some statements.

D) I don't know why this is wrong : if according to premise #3 someplanning commitee members work in suburbs , can we not infer that some dont work there ?

E) CORRECT : this is the result of premise 1 and 2.

Thank you so much
Sherry

[David Boyle]

Hello and happy holidays !
I am so obsessed with this question that I sneaked away from my Christmas party just to write a question about this !
I have been working on this for a few days and it's bugging me. Could you please see where I am going wrong with my reasoning ? Particularly - I have an issue getting rid of D.


Planning committee members <SOME > Financial interest
Planning committee members --> do not work in suburbs
Planning committee members <SOME> Work in suburbs

A) WRONG : (financial -> are in the construction industry ) this is making an all statement about the some group .

B) WRONG : this is making an all statement about the some group again. We only know about some financial interes groups not working.

C) WRONG: this is overlapping the two some statements.

D) I don't know why this is wrong : if according to premise #3 someplanning commitee members work in suburbs , can we not infer that some dont work there ?

E) CORRECT : this is the result of premise 1 and 2.

Thank you so much
Sherry

Hello Sherry001,

"sneaked away from my Christmas party just to write a question about this ! " Now that's dedication!

Anyway, first off, you may want to correct "Planning committee members --> do not work in suburbs" to

"Planning committee members --> do not live in suburbs".

As for answer A, it may resemble a mistaken reversal, since it says, "sig financial interests constr. industry", whereas the stimulus says "plan. com. members in const. industry sig financial interests".

Answer B is overbroad, since many people not on the committee may also have big financial interests.

As for answer D, actually, you can't infer that some don't work in the suburbs; we don't know that. Just as with answer C, you can't assume that some DO work in the suburbs: in answer D, you can't assume that some DON'T! Heh heh. Watch those unwarranted assumptions!

Hope this helps,
David

[lsathml]

Hello!

For this question I had originally selected E but then eliminated it as I considered it a trick answer.

'some persons with significant financial interests in the planning committees decisions' > I realised that it was missing 'some persons on the committee with financial interests.'
Without specifying they're on the committee, could this not just refer to ANY person who has a financial interest in the committees decisions? If so, then we know nothing of where they live or work as the stimulus refers only to committee members.

The only thing I can think of why this would be correct is the 'some train', so because some of the committee members have financial interests, and NO committee members live in the suburb, therefor SOME people who have financial interests do not live there (as some of those are committee members). But I cant diagram it correctly,
1) PCM<-->FI (some committee members have financial interest)
2) PC---> /Suburbs (No committee members live in the suburbs) which can be reduced to PC<--->/suburbs (some committee members dont live in suburbs)
But I dont see how to connect the 1st and second, as the similar element is committee members. Or is the some train not applicable in this instance?

Thank you

[Eric Ockert]

Hi there!

I think you are on the right track here. To capture the two rules we have:

"Some planning committee members...have significant financial interests in the committee's decisions."
PCM SFI

and

"No one who is on the planning committee lives in the suburbs."
PCM Sub

The trick here is that "some" statements are completely reversible. Once we reverse the first rule we have:
SFI PCM

which can now be linked to the second rule:
SFI PCM Sub

So, if we drop the common term of "PCM" we can conclude that:
SFI NOT Sub (Some people with Significant Financial Interests in the committee's decisions do NOT live in the Suburbs).

Hope that helps!

[lsathml]

Hi there!

I think you are on the right track here. To capture the two rules we have:

"Some planning committee members...have significant financial interests in the committee's decisions."
PCM SFI

and

"No one who is on the planning committee lives in the suburbs."
PCM Sub

The trick here is that "some" statements are completely reversible. Once we reverse the first rule we have:
SFI PCM

which can now be linked to the second rule:
SFI PCM Sub

So, if we drop the common term of "PCM" we can conclude that:
SFI NOT Sub (Some people with Significant Financial Interests in the committee's decisions do NOT live in the Suburbs).

Hope that helps!

Great thank you! Makes perfect sense, forgot that they can obviously be reversed.

[jessicamorehead]

Alright, these "some" ones always trip me up. I want to make sure I thoroughly understand it so I can be confident when I face these questions in the future. Here's how I diagrammed. Can someone confirm my logic?

Stimulus:
1. PCM (those representing CI) SOME significant financial interest
2. PCM (includes all of them) NOT live in subs
3. PCM SOME work in subs

I changed "many" to "some" since they both mean, "at least one." Is that okay to do?? I understand if there was a "most" that would be a different story, since that means "more than half."

I also thought that the first sentence "those representing the construction industry" was important to note, because it is a subcategory of the planning committee members. Therefore, it is safe to assume that PCM (those representing CI) is included in PCM, but not all PCM are represented in the CI. Is that correct?

I then substituted #1 into the PCM portion of #2 and then #3 into the PCM portion of #2 to make two distinct inferences:
1+2) PCM (those representing CI) SOME significant financial interest NOT live in subs
3+2) PCM SOME work in subs NOT live in subs

I found that answer choice E clearly represented SOME significant financial interest NOT live in suburbs.

I eliminated A because we don't know anything about those "IN the construction industry." Those who represent it, may not even be "in" it.

I eliminated B because it lacked the "some" that needed to be carried over.

I eliminated C because it tried connecting my inferences that weren't even connected (SOME significant financial interest and SOME work in suburbs are not connected, they just share a necessary side).

I eliminated D because it too tried to connect two distinct ideas. PCM (those representing CI) does not connect to working in the suburbs.

Let me know if my logic is valid. I know I need to get quicker at this, so I do understand that I could have just reversed the PCM SOME significant financial interests into significant financial interests SOME PCM and connected that directly into PCM NOT live in subs. But how did you know that that the "representing construction industry" distinction was not necessary to include?

Thanks in advance!

[Alex Bodaken]

jessicamorehead,

Thanks for your question. Let me try and break my answer up in a couple of parts:

1.) Changing many to some is totally fine - as you note, they both mean "at least one but less than all"

2.) In terms of how to think about PCM and representing CI (I'll call that RCI) - two things. Number one, yes, all of those who represent the construction industry and are PCMs are PCMs, and the reverse isn't really applicable because RCI is a descriptor of some PCMs. Let me describe it this way: all blue shorts are shorts, but not all shorts are blue. So you are correct there. Second, the RCI thing does end up being irrelevant, but we don't know that to start.

3.) Now to the answer choices...

(A) isn't really wrong because of the distinction you note. But the logic is wrong - if "No persons with significant financial interests in the planning committee’s decisions are not in the construction industry" then that would mean all persons with significant financial interests in the planning committee’s decisions are in the construction industry. But we don't know that to be true: it is a mistaken reversal of the (correct) fact that all planning committee members representing the construction industry (PCMRCI) have significant financial interests in the committee's decisions (SFICD) - PCMRCI SFICD. The mistaken reversal would be SFICD PCMRCI, in other words, that all people with significant financial interests in the planning committee’s decisions are in the construction industry...but that isn't necessarily true.

I think that the logic for the rest of your eliminations is sound.

4.) As to how to get to the answer a bit faster...as I noted above, we can't quickly see that RCI is irrelevant. But thinking about this answer non-conditionally is another way to approach it (not necessarily better, just different). As I thought through this answer, I thought about PCMs being broken into groups...theres a group of PCMs who are SFICD (could call them PCMSFICD), and those who aren't (PCMSFICD). In both of those groups, no one lives in the suburbs (because no PCS live in the suburbs). Therefore, some SFICDs don't live in the suburbs because we know there is a group of PCMSFICDs, and all of them don't live in the suburbs. I know I've said this before, but sometimes thinking about the questions less conditionally and more broadly can help us get to the answer.

I hope that helps!
Alex

[conorrjohnston]

Hi!

This question has me a little confused as to why C and D are eliminated.

Here's how I mapped it.

Planning Committee Members Sig Financial Interests
Planning Committee Members <-NONE I -> (X) Live in Suburbs
Planning Committee Members Work in Suburbs.

As a result, to justify answer choice C, I map: PCM -SOME> Work in Suburbs. ; Some can mean many, many on the planning committee purportedly work there, and therefore answer choice C felt great to me.

D was also tripping me. I'm not sure why. I think the ultimate problem with this question for me is that all of the answers seem kind of fine. I can DEFINITELY see why (E) is right with the following mapping: PCM SFI (X) LIVE IN SUBURBS. But C also feels fine? Help!!