Q19 - An editor is compiling a textbook

[ohthatpatrick]

What does the Question Stem tell us?
Inference (must be true)

Break down the Stimulus:
Read to combine ideas, using Conditional, Causal, Quantitative, or Contrast language.

The 2nd sentence is kinda mathy. There will be 1 or 2 of these three guys in the book, but not all three. 3rd sentence is conditional. If K, then J. Combining those two ideas allows us to say "if K, then J, which means NOT L." (otherwise we'd have all three) The contrapositive of that would be "if L, then NOT J, and then NOT K".

Any prephrase?
The possibilities are KJ, LJ, L alone, or J alone.

Correct answer:
A

Answer choice analysis:
A) This is true. We never see L with K. If we have L and add K, it would bring in J, which would be an all-3 no no.

B) Nope, could be KJ.

C) Could be KJ.

D) Nope, L would be alone.

E) No, it could be KJ or J alone.

Takeaway/Pattern: Like almost all correct answers to Inference questions, this correct answer was obtained by combining two or more claims, using Conditional, Causal, Quantitative, or Contrast language. This question feels more like Games than most LR questions, since it really has the inferential flavor of an In/Out game.

#officialexplanation

[jardinsouslapluie5]

This was more like on logic game.
I want to make sure something.

In the stimulus, it says "essays by SEVERAL different AUTHORS."
Several from these three? or there would be others?
Are they saying that there are others, but at least one of them from L, K or J? I mean, if it's not, (D) must be true, isn't it?

Because the rule:
K→J
K→/L

K or L must be out.
So When L is in, K must be out, therefore to be SEVERAL there MUST BE J.

Please correct me if I am missing something.
Thanks.

[patrice.antoine]

Jardin, also note the second sentence and one of the most important statement "...it will not contain all three"

So we know there will be two essays of some sort chosen. For the last sentence, also don't forget to negate K-->J:

~J-->~K (which would mean we must have L, and if we have L we MUST have J with that L (as K cannot be with L because having K will mean we must have J which would violate the rule of having all three (KJL).

So there are only two possible options here:

KJ OR JL

From this we can attack the questions. Answer choice (D) is COULD BE TRUE because it can go both ways (if L -->J but also if J-->L). Neither is dependent on the other happening.

(A) is absolutely positively true because we know for certain if L is in, K is definitely out, because having K would mean having J and we cannot have all three. Another way to state this in a conditional statement:

Conditional: K --> J and ~L

Contrapositive: L or ~J --> ~K


Hope this helps!