PT56 Logic Games (LG) explained
Posted: Tue Jun 01, 2010 12:12 am
I found this section of PT56 to be very difficult. In retrospect, I see it really played to my weaknesses. So to get over it, I thought I would figure them out and act as if I was teaching it to someone else. And as long as I was doing that, I figured I would post it on here.
So on to question one, which took a stupid 13 minutes for me to do.
This is a pretty straightforward linear game with only one level to worry about. The problem is that the rules, although they contain overlapping elements, are not easily combined into a single diagram. I've seen other people use four templates to solve this, but this is not something that I think I would do on a test day. It just seems too risky, in that you could go through all the work and one error messes you up, or perhaps it's even not helpful.
So I decided to keep the rules separate
Here is the diagram I came up with: http://www.psych.ubc.ca/~jchin/diagrams/Image14.jpg
It basically just has the not laws inferred from the rules, and the G < K rule is combined with the rule that G and L are next to each other with a G/L < K rule. Note F is a floater
On to the questions!
1. This is your basic apply a rule question, nothing too difficult, E turns out to be the right answer
2. This is a global question, kind of scary to see on an already scary first game. But if you just take them one at a time:
A seems very plausible and since J and L are only separated by one it seems even likely that L will also be before H. I didn't cross it off but moved on. Then B just follows from the basic G/L<K inference, so it's the right answer. Quite a relief.
3. So this question would seem to follow straight from our not-laws in the diagram. But given the lack of a cohesive diagram and the possibility of weird interactions, I decided to just make a quick side diagram to see if K could indeed be 3rd:
G-L-K-J-H/F-F/H
Yup, and it turned out this diagram would come in handy later!
4. This was the hardest one to this point. There are basically two options here, start plugging in like mad or try to solve it theoretically. I just plugged in, but in retrospect there was a better way. I think the best thing to do is think about which application would cause the greatest amount of restrictions. I liked the ones that applied J or L to 2 or 5 o'clock because these led to a clear placing of the other L/J and blocked off a space. Then the J at 5 is especially nice because it pins in the H as well, a double force.
Plugging it in shows this is the right answer.
5. This one seemed damned intimidating at first, but I think this is one where it plays to go with your instincts. I didn't and tried something that seemed more appropriate. But here is what I think is the right way to do it.
If F can't be first, then only G/J/L can be. Although it may seem like a bad idea, go ahead and do a minidiagram for all of those. They each allow some placement because each are involved in big rules.
then looking at the answer choices, A seems imminently possible. the others seem very impossible given these were used up in all the choices. Should have gone with my gut!
6. I messed this one up big time. E, in retrospect, follows from my initial not laws. I figured I should go through all of them and this took tons of time.
Question two will be up soon!
So on to question one, which took a stupid 13 minutes for me to do.
This is a pretty straightforward linear game with only one level to worry about. The problem is that the rules, although they contain overlapping elements, are not easily combined into a single diagram. I've seen other people use four templates to solve this, but this is not something that I think I would do on a test day. It just seems too risky, in that you could go through all the work and one error messes you up, or perhaps it's even not helpful.
So I decided to keep the rules separate
Here is the diagram I came up with: http://www.psych.ubc.ca/~jchin/diagrams/Image14.jpg
It basically just has the not laws inferred from the rules, and the G < K rule is combined with the rule that G and L are next to each other with a G/L < K rule. Note F is a floater
On to the questions!
1. This is your basic apply a rule question, nothing too difficult, E turns out to be the right answer
2. This is a global question, kind of scary to see on an already scary first game. But if you just take them one at a time:
A seems very plausible and since J and L are only separated by one it seems even likely that L will also be before H. I didn't cross it off but moved on. Then B just follows from the basic G/L<K inference, so it's the right answer. Quite a relief.
3. So this question would seem to follow straight from our not-laws in the diagram. But given the lack of a cohesive diagram and the possibility of weird interactions, I decided to just make a quick side diagram to see if K could indeed be 3rd:
G-L-K-J-H/F-F/H
Yup, and it turned out this diagram would come in handy later!
4. This was the hardest one to this point. There are basically two options here, start plugging in like mad or try to solve it theoretically. I just plugged in, but in retrospect there was a better way. I think the best thing to do is think about which application would cause the greatest amount of restrictions. I liked the ones that applied J or L to 2 or 5 o'clock because these led to a clear placing of the other L/J and blocked off a space. Then the J at 5 is especially nice because it pins in the H as well, a double force.
Plugging it in shows this is the right answer.
5. This one seemed damned intimidating at first, but I think this is one where it plays to go with your instincts. I didn't and tried something that seemed more appropriate. But here is what I think is the right way to do it.
If F can't be first, then only G/J/L can be. Although it may seem like a bad idea, go ahead and do a minidiagram for all of those. They each allow some placement because each are involved in big rules.
then looking at the answer choices, A seems imminently possible. the others seem very impossible given these were used up in all the choices. Should have gone with my gut!
6. I messed this one up big time. E, in retrospect, follows from my initial not laws. I figured I should go through all of them and this took tons of time.
Question two will be up soon!