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Either/Or Conditional Reasoning

Homey
• Posts: 1
• Joined: Jul 10, 2011
#798
Question # 5 pg 151
ED = Economy Downturn
I tried to attach file but the site did not accept .doc or .docx---I do have the arrows and the slashes in but I am not sure if they are listed.

Thanks,
Traci

FNG = Food Not Good
NRS = No Restaurant Survive

Diagram : ED or FNG NRS
Contrapositive: NRS ED and FNG

Question #6 pg 152

Is the following correct?

Diagram: Feast Famine Feast Famine
Contrapositive: Famine Feast Famine Feast
Dave Killoran
• PowerScore Staff
• Posts: 4263
• Joined: Mar 25, 2011
#803
Hey Traci,

Thanks for the message. Yes, usually the discussion board won't accept uploads because so many spammers are out there (it will accept image uploads, however). Whenever you want to ask a question, you can use the "~" for a negative, or just put the word NOT before the term. An arrow can be displayed with two dashes and then the greater than sign: -->

Without the negatives or arrows, I can't really tell if your diagrams are correct, but the answer key in the book--on pages 154-155—is correct. If you can specify what is bothering you, I'll definitely take a look at the question and answer you back.

Thanks!
amandarruff@aol.com
• Posts: 1
• Joined: Aug 28, 2013
#10622
Hi,

I have been having massive problems with the conditionals and misrepresentation. I seem to misplace the necessary and sufficient. I have several examples of what I am missing. From Page. 151

#3 If the weather is good and we get approval from the city, we will hold the race on Saturday.

I put down

If R then WG and A : Where R= Race on Sat. and WG= Weather is good and A= Got approval from the city.

It is necessary for the the weather to be good and the city to approve the race in order for the race to be Sat. So I am thinking about it like this if "R" happens then "WG and A" must also happen. And that "WG and A" happen then R can happen.

Like wise #5 If the economy has a downturn (ED) or if the food is not good (BF), the restaurant will not survive(~R). I had down: If ~R then ED or BF likewise contrapositive is:
if ~ED and ~BF then R. R indicates that there was an ED or BF and and ED or BF is required in order for the ~R. I don't understand how the Restaurant not surviving is requires for their to be an economic downturn or the good not being good, logically that makes 0 sense.

#7 The flight will be cancelled (FC) if it snows in Buffalo ( SB)or the plane has mechanical problems (MP). I had down: If FC then SB or MP Where the flight being cancelled indicates that either MP or SB or both occurred. and that MP or SB had to happen for FC to occur. I don't know how fc has to happen for their to be SB.

What am I doing wrong? If you need more info from me I would be happy to post more of what I am seeing and why I don't understand it.
Dave Killoran
• PowerScore Staff
• Posts: 4263
• Joined: Mar 25, 2011
#10628
Hi Amanda,

Thanks for the questions. What you are doing here that is causing problems is that you are trying to figure out how these problems would work in the real world. In doing that, you are ignoring what the author actually is saying, and the whole goal is to identify exactly what the author is thinking. For more on that general idea, please see this prior post I made about it: http://forum.powerscore.com/lsat/viewto ... 557#p10557.

Looking at your specific questions, let's start with #3. What is the conditional indicator? The word "if" is the big one, and you should almost think about that as if it is blinking in red neon Once I see that word, I know that what comes after it is sufficient (WG + AC), and then the last part is the necessary condition (RS). And in that way I see the relationship quickly and easily, and you might notice I don't even stop to think about how weather affects a race, etc. In other words, I ignore what I think about those topics in the real world, and just use the language of the author to determine what was said.

Now look at #5--where is the "if?" Same things as the above and then we follow the same reasoning to diagram the statement.

In #7 the "if" moves into the middle of the sentence, but other than that the same reasoning is applied.

The rule here is: follow the indicators because they tell you what that author is saying. Do not try to think about how ti would work in the real world because not all of the statements made by LSAT speakers mirror the real world.

Please let me know if that helps. Thanks!
Katya W
• Posts: 42
• Joined: Dec 03, 2019
#74330
I have a question about #7 in Either/Or Conditional Reasoning.

“The flight will be cancelled if it snows in Buffalo or the plane has mechanical problems.”

I diagrammed correctly, with “SB or MP” being sufficient and “Flight cancelled to Buffalo” being necessary. However, what I did differently is I put a slash through “Flight cancelled to Buffalo” because I took it as a negative - I wrote “flight cancelled to Buffalo” as “FB” (flight to buffalo) and then slashed it to represent cancelled flight, or no flight “/FB”.

Is this also a valid option? It means the same thing I believe.

Thank you!
Katya
Last edited by Katya W on Thu Mar 12, 2020 12:21 pm, edited 1 time in total.