LRB Question on conditional reasoning, p. 156 Forum

[M.M.]

Ok, so the drill is to diagram conditional statements, and the statement is:

9. Unless they find an eyewitness and put the defendant on the stand, they will lose the case.

Using LRB's approach to unless statements, which is:

1. Whatever term is modified by “unless,” “except,” “until,” or “without” becomes the necessary condition.
2. The remaining term is negated and becomes the sufficient condition.

I diagrammed

~LC (they will NOT lose the case) -> F.E. and P.S. (if they find an eyewitness and put the defendant on the stand).

Contrapositive: ~F.E. or ~P.S. -> LC (if they don't find the eyewitness or put the defendant on the stand, they will lose the case.

I seem to be doing this problem right according to the formula, but the answer key says the diagram should be:

LC -> FE and DS (if they lose the case, then they found an eyewitness and put the defendant on the stand [I wrote the written out sentences that correspond with these two diagrams btw).

~FE or ~DS -> ~LC (if they don't find an eyewitness or they don't put the defendant on the stand, they will not lose the case)

Not only does this seem against the formula, but it's highly counterintuitive. What am I doing wrong?

[cahwc12]

looks like you either mis-read/mis-transcribed or a double negative got the better Mr. Killoren! It's a 500 page book so there are bound to be some errata on the website, despite their best efforts to remove them.

I diagrammed it as
~L ---> FE and PS
~PS or ~FE ---> L

[Jeffort]

One thing you are most likely doing wrong is breaking the law by using a pirated pdf version of the LRB you downloaded/pirated from a torrent instead of just buying a legit hard copy of the book like most honest people.

There was a typo on that drill in the original first few batches of the LRB that were printed when the book was first released many years ago.

The typo error on that page was found and fixed pretty fast not long after the LRB was first published and all copies printed since then are free of the error. The stolen and pirated pdf version of the LRB floating around on torrents is the original edition which contains that typo and a few others.

That's what you get for stealing (if you did). Not a really great or smart way to try to begin a legal career, especially by posting a complaint about the goods you likely stole on a public forum with details that indicate beyond much doubt that you pirated the book. Ethics failure and stupid criminal success!

If not that and you are working from a legit bound book hardcopy that contains the error, then you managed to get a really old and dusty hand me down copy of the LRB that was printed a bunch of years ago and is somehow still floating around, which is unlikely, but possible. If this is the case, watch out for silverfish and other insects that might be living in the book!

http://www.powerscore.com/lrbible/content_index.cfm

Current Bible Corrections
The currently available version of the PowerScore LSAT Logical Reasoning Bible contains no known errors. To view a list of errors from previous editions, please visit here.

Previous Logical Reasoning Bible Edition Corrections:
http://www.powerscore.com/lrbible/conte ... ctions.cfm

Seriously, I hate to be harsh, but you are trying to get into law school to become a lawyer, so you should try to obey the law. If you did pirate the thing, do the right thing and order a legit copy, someday after LS you are going to want people to pay you for stuff you write.