PT 22 June '97 LG 15-19 "Paintings on the wall". Forum

[bkbkbk]

If anyone can help explain this to me I would be very appreciative as I have racked my brain for 2 days over what must be a simple concept. I know we are not supposed to post lsat questions so if anyone that has this particular PT and fully understands this question would be willing to PM me so I can ask you a specific question that pertains to the 1st and 4th rule, it would help me immensely. I littlerally had a dream about this problem last night and cannot get it out of my mind.

[skip james]

O <---> NOT P

contrapositive: P <----> NOT O

19 <-----> NOT 20

20 <------> NOT 19

[thegor1987]

r u talkin about the game with the 19th and 20th century paintings that are either oil or watercolor?

[skip james]

r u talkin about the game with the 19th and 20th century paintings that are either oil or watercolor?

yup.

the 1st rule just means [O/W]

the 4th means [19/20]

[thegor1987]

yea I can't seem too find it (are you sure it's PT 22?) but I remember it's really easy once you make that one inference, it's just not a traditional game which can scare you and cause you to lose focus.

[skip james]

yea I can't seem too find it (are you sure it's PT 22?) but I remember it's really easy once you make that one inference, it's just not a traditional game which can scare you and cause you to lose focus.

yup 22. 3rd game, section 3, i think.

[bkbkbk]

Ok here is my deal (and I know this is flawed because the game is always right), I understand it cannot be both a 19 and 20 so we have the 19/20. And likewise I know we cannot have both O and W so we have O/W.

My thing is the beginning of the first question tells us all 19s are Ws (19--->W) and in order to get the question right we must assume that if all 19s are W then all 20s are O's. But what if All 19s are Ws and at least one 20 is a W?

The first time I did this question 2 months ago I did it like the game wants me to, assuming if 19 is W then 20 cannot be W but when i did it this time I noticed that I don't see anything in the rules that convey that and if this were a LR question it would likely be testing if I would make a mistaken assumption.

[skip james]

Ok here is my deal (and I know this is flawed because the game is always right), I understand it cannot be both a 19 and 20 so we have the 19/20. And likewise I know we cannot have both O and W so we have O/W.

My thing is the beginning of the first question tells us all 19s are Ws (19--->W) and in order to get the question right we must assume that if all 19s are W then all 20s are O's. But what if All 19s are Ws and at least one 20 is a W?

The first time I did this question 2 months ago I did it like the game wants me to, assuming if 19 is W then 20 cannot be W but when i did it this time I noticed that I don't see anything in the rules that convey that and if this were a LR question it would likely be testing if I would make a mistaken assumption.

nah that's wrong.

if (and im just going off what you said) 19 --> W

then (NOT W --> NOT 19) or... Oil --> 20

NOT

20 --> Oil

[skip james]

but what if All 19s are Ws and at least one 20 is a W?

19 ---> W

O --> 20 doesn't mean that 20 ---> O

in other words:

All oils are 20s is not the same as all 20s are oils.

[bkbkbk]

Skip, I understand you on both counts. The second part you mentioned "O --> 20 doesn't mean that 20 ---> O" is spot on as well but it was the:

if (and im just going off what you said) 19 --> W

then (NOT W --> NOT 19) or... Oil --> 20

that I was not fully grasping. It has been a good 4 months since I have touched my informal logic materials and it looks like I could use a refresher. Thanks a lot, I really appreciate this.

[skip james]

Skip, I understand you on both counts. The second part you mentioned "O --> 20 doesn't mean that 20 ---> O" is spot on as well but it was the:

if (and im just going off what you said) 19 --> W

then (NOT W --> NOT 19) or... Oil --> 20

that I was not fully grasping. It has been a good 4 months since I have touched my informal logic materials and it looks like I could use a refresher. Thanks a lot, I really appreciate this.

no prob.