I'm having trouble approaching these question types that appear in the newer logic games: Which one of the following , if substituted for (insert rule), would have the same effect?
I spent alot of time on this question and still missed it. I don't really have a plan of attack when I have a question like this. I'm not sure what I'm supposed to be looking for. Any advice on how to approach them?
LG help: PT59 S1 Q10 Forum
-
- Posts: 47
- Joined: Sat Jan 15, 2011 2:50 am
LG help: PT59 S1 Q10
Last edited by vamos on Tue Mar 08, 2011 1:24 pm, edited 1 time in total.
- Jack Smirks
- Posts: 1330
- Joined: Sat May 15, 2010 5:35 am
Re: LG help: PT59 S1 Q10
Here's a good discussion: http://www.top-law-schools.com/forums/v ... 6&t=117641vamos wrote:I'm having trouble approaching these question types that appear on the newer logic games: Which one of the following , if substitued for (insert rule), would have the same effect?
I spent about alot of time on this question and still missed it. I don't really have a plan of attack when I have a question like this. I'm not sure what I'm supposed to be looking for. Any advice on how to approach them?
-
- Posts: 1710
- Joined: Wed Sep 16, 2009 12:01 am
Re: LG help: PT59 S1 Q10
See the various links in this topic for details on this question type. (Was beat on the link; same as above.)
For this specific question, the rule in question is that H is not first and H is before K. Now, we know from the first clue that G and K are related elements — they're next to each other — so our best bet is that the right answer is going to have something to do with G. Only B and D have to do with G, so it's probably one of those. It's not B, because we know that something other than F or M could be first; for example you could have L I M H G K F, which would put L first. B therefore makes something impossible that was possible before.
D, on the other hand, works: if H is not second, then it's between M and G. M, we know, is one of the first three; if H is third or later, M is before it, which means that H is after it, and H being before G also puts it before K, as before. If H is second, then, well, it's before K anyway (because K is not first — it needs G before it), and it's not second. Thus, it has an equivalent effect.
For this specific question, the rule in question is that H is not first and H is before K. Now, we know from the first clue that G and K are related elements — they're next to each other — so our best bet is that the right answer is going to have something to do with G. Only B and D have to do with G, so it's probably one of those. It's not B, because we know that something other than F or M could be first; for example you could have L I M H G K F, which would put L first. B therefore makes something impossible that was possible before.
D, on the other hand, works: if H is not second, then it's between M and G. M, we know, is one of the first three; if H is third or later, M is before it, which means that H is after it, and H being before G also puts it before K, as before. If H is second, then, well, it's before K anyway (because K is not first — it needs G before it), and it's not second. Thus, it has an equivalent effect.
-
- Posts: 47
- Joined: Sat Jan 15, 2011 2:50 am
Re: LG help: PT59 S1 Q10
Thanks for the link, it was very helpful.
As for this particular question, I simply skipped answer choice (D) because the wording is confusing, it has 2 necessary conditions: unless H2, it must be between M and G. What is the proper diagram for a statement with two necessary conditions and no sufficient condition?
tomwatts, what was your reasoning for diagramming this statement as ~H2 --> M-H-G? You chose to diagram what followed unless as the sufficent condition and you negated it. In that sense, it seems like the proper way to diagram a statement with two necessary conditions and no sufficient condition is to select one of the necessary conditions and convert it into a sufficient condition + negate it.
As for this particular question, I simply skipped answer choice (D) because the wording is confusing, it has 2 necessary conditions: unless H2, it must be between M and G. What is the proper diagram for a statement with two necessary conditions and no sufficient condition?
tomwatts, what was your reasoning for diagramming this statement as ~H2 --> M-H-G? You chose to diagram what followed unless as the sufficent condition and you negated it. In that sense, it seems like the proper way to diagram a statement with two necessary conditions and no sufficient condition is to select one of the necessary conditions and convert it into a sufficient condition + negate it.
- EarlCat
- Posts: 606
- Joined: Mon Mar 12, 2007 4:04 pm
Re: LG help: PT59 S1 Q10
Think of how necessary conditions are changed into (negated) sufficient conditions when writing the contrapositive.vamos wrote:Thanks for the link, it was very helpful.
As for this particular question, I simply skipped answer choice (D) because the wording is confusing, it has 2 necessary conditions: unless H2, it must be between M and G. What is the proper diagram for a statement with two necessary conditions and no sufficient condition?
In ~A-->B, B is necessary. In the contrapositive, ~B-->A, ~B is sufficient. So for "You must have A unless you have B," either A or B can be negated and used as the sufficient for the other.
Same thing here. Either H2 or M-H-G can be negated and used as the sufficient condition for the other.
The simplest way to look at it is to replace "unless" with "if not."tomwatts, what was your reasoning for diagramming this statement as ~H2 --> M-H-G? You chose to diagram what followed unless as the sufficent condition and you negated it. In that sense, it seems like the proper way to diagram a statement with two necessary conditions and no sufficient condition is to select one of the necessary conditions and convert it into a sufficient condition + negate it.
If not H2 (i.e. if H is not 2) then H must be between M and G.
~H2 --> M-H-G
I haven't looked at the game, but if there's not a rule that M is before G, make sure you indicate that M-H-G could be reversed.
-
- Posts: 47
- Joined: Sat Jan 15, 2011 2:50 am
Re: LG help: PT59 S1 Q10
After further reviewing, I have a much better understanding. There's two ways of diagramming unless statements:
A unless B (~A --> B)
or
If not B, then A (~B --> A)
I was used to diagramming unless statements in the first form, but this problem is a good example of why it's good to practice both.
As EarlCat stated, It would have been more simple to use the second form: If not H2 --> M-H-G.
Thanks for all the responses!
A unless B (~A --> B)
or
If not B, then A (~B --> A)
I was used to diagramming unless statements in the first form, but this problem is a good example of why it's good to practice both.
As EarlCat stated, It would have been more simple to use the second form: If not H2 --> M-H-G.
Thanks for all the responses!
Want to continue reading?
Register now to search topics and post comments!
Absolutely FREE!
Already a member? Login