Q: Some people on the finance committee are also on the defense committee, and the majority of people on the defense committee are on the health committee.
A1: Some people on the health committee are also on the finance committee.
A2: There are some people on the finance committee and some people on the health committee who are also on the defense committee.
Having trouble understanding why A1 does not work.. any help would be appreciated!
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- maryadkins
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Atticus Finch
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Re: 2388
Say we have this:
Finance committee: 10 people
Health committee: 10 people
Defense committee: 10 people
The first sentence tells us that some on finance are on defense. Okay, so we're going to go with the minimum interpretation (always a good when you're looking for necessary overlaps): 1 person. One person is on both F and D.
Now, we're told that most of the people on D are on H. We'll go minimum, so that means 6. Six of the 10 people on D are in H.
So on the D committee, we have:
6 people who are also on H
1 person who is on F
3 unknowns
A1 need not be true, because there is no required overlap.
Hope this helps.
Finance committee: 10 people
Health committee: 10 people
Defense committee: 10 people
The first sentence tells us that some on finance are on defense. Okay, so we're going to go with the minimum interpretation (always a good when you're looking for necessary overlaps): 1 person. One person is on both F and D.
Now, we're told that most of the people on D are on H. We'll go minimum, so that means 6. Six of the 10 people on D are in H.
So on the D committee, we have:
6 people who are also on H
1 person who is on F
3 unknowns
A1 need not be true, because there is no required overlap.
Hope this helps.
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- Kcb77
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Thanks Received: 1
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Vinny Gambini
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- Joined: May 13th, 2016
Re: 2388
Okay, this question is not difficult--I thought it was, but its not.
If you didn't know, you can draw a parallel inference from All-All, Most-Most, and All-Some relationships, i.e.,
A --> B, and Most A --> C. Therefore, Some B <--> C. However, parallel inferencs cannot be drawn from Some-Some relationships, nor from Most-Some relationships (A2 is waiting for you to run a foul of this by saying Some Health committee members are on the Finance committee--there is not enough information present to draw that inference). Additionally, although reversing Sufficient and Necessary assumptions without justification is wrong, i.e., A --> B does not mean
B --> A. You can however infer that if all A is B, then Some B is A. Likewise, if Most A is B, then some B is A; and if some A is B, then some B is A.
The question's stimulus says that SOME Finance committee members are on the Defense committee, and that MOST Defense committe members are on the Health committee. This is a Most-Some relationship, and thus no parallel inference can be drawn from it. However, we do know that since Some Finance committee members are on the Defence committee, then Some Defence committee members are on the Finance committee. We also know that since Most Defense committee members are on the Health committee, then Some Health committee members are on the Defense committee. Therefore, there are Some Health committee members on the Defense committee, and Some Finance committee members on the Defense committee. A1, the correct answer, says this but in that sometimes-unfamiliar-LSAT-language kind of way, "There are Some members of the Finance committee and Some members of the Health committee who are on the Defense committee". This is not to be confused with the statement Some Finance committee members on the Health Committee are on the Defense committee.
I hope this helps,
Good luck
If you didn't know, you can draw a parallel inference from All-All, Most-Most, and All-Some relationships, i.e.,
A --> B, and Most A --> C. Therefore, Some B <--> C. However, parallel inferencs cannot be drawn from Some-Some relationships, nor from Most-Some relationships (A2 is waiting for you to run a foul of this by saying Some Health committee members are on the Finance committee--there is not enough information present to draw that inference). Additionally, although reversing Sufficient and Necessary assumptions without justification is wrong, i.e., A --> B does not mean
B --> A. You can however infer that if all A is B, then Some B is A. Likewise, if Most A is B, then some B is A; and if some A is B, then some B is A.
The question's stimulus says that SOME Finance committee members are on the Defense committee, and that MOST Defense committe members are on the Health committee. This is a Most-Some relationship, and thus no parallel inference can be drawn from it. However, we do know that since Some Finance committee members are on the Defence committee, then Some Defence committee members are on the Finance committee. We also know that since Most Defense committee members are on the Health committee, then Some Health committee members are on the Defense committee. Therefore, there are Some Health committee members on the Defense committee, and Some Finance committee members on the Defense committee. A1, the correct answer, says this but in that sometimes-unfamiliar-LSAT-language kind of way, "There are Some members of the Finance committee and Some members of the Health committee who are on the Defense committee". This is not to be confused with the statement Some Finance committee members on the Health Committee are on the Defense committee.
I hope this helps,
Good luck
3 posts Page 1 of 1