I still don't get the logic in this question.

If not all fish swim in the sea (F -> SS or F -> ~ SS)

How does the fact that SLC -> SS mean that some fish are SLC?

The only thing I can logically conclude is that SLC can either be a F or not a F.

The correct diagram for "it's not true that P implies Q" is "~(P --> Q)".

In our example, we have "The claim that fish only swim in the sea has no merit".

This is equivalent to "it's not true that fish only swim in the sea."

So, when diagrammed, we have ~(F --> SS).


This just means that you cannot conclude that if you have F, you have SS. You could have fish swimming in the sea, or a river, or a fish bowl--whatever. ALL you know is that they don't NECESSARILY swim in the sea.

The diagram "~(F --> SS)" can be translated to read "F + ~SS".


So now we know two things:

1. ALL SLCs swim in the sea.

and

2. AT LEAST some fish do not swim in the sea.

Therefore, some fish are not SLCs.


If you want more detail on the "~(F --> SS)"/"F + ~SS" relationship, check out this link:
http://www.regentsprep.org/regents/math/geometry/GP1/negatecompound.htm

Oh, and you're right Joseph.

You can conclude that "SLC can either be a F or not a F".

Another way of saying this is that F can be something other than an SLC. (Since there are some SLCs that are NOT F's, and since at least some F's do not swim in the sea, AT LEAST some SLCs and Fs are mutually exclusive).

And this coincides with the correct answer choice: "not all fish are strange looking creatures."

We weren't just referring to just any type of strange looking creatures, but specifically to "these strange looking creatures". That's why I chose E rather than B. The question should be revised because it's not clearly written. Thank you.

Shawn,

Thanks for your feedback.

We intended to make the Exercise questions vague/slightly ambiguous, because LSAT question often contain vague/ambiguous language.

That said, this question is probably too ambiguous. Look for a revision in the next update.

Thanks.