LG Game 1 Question 5 Explanation, by LSATHacks
This question asks how to completely determine who is in. You shouldn’t just try answers randomly – you should have a plan.
The answers are all in terms of who is out. So the key is to ask which workers produce an effect if they are out.
All of the answers place 2/7 workers out. So if a workers knocks out someone else, we are missing 3/7, with only 4/7 left to place in.
So, who knocks someone out, by being out? That’s pretty much only T. If T is out, S is out.
Looking through the answers, only B has T: it knocks out both T and Q. So with B we get this setup:
So only RVWX are left to place. We need three of them. W can’t be in, because they would knock out both R and V. So RVW must be chosen. And R must be leader (rule 1).
So B is CORRECT. There’s no need to try other answers (we already checked to see if any others had T).
This isn’t magic. I did this in timed conditions. I predicted that the right answer would have to knock out one other person, and tested B on that basis. The LSAT loves to leave shortcuts like this for you to find.
(Of course, in timed conditions, I read all the answers. But that’s not the same thing as exhaustively disproving those. There’s no sense in that, when you’ve already made a prediction, found it, and proved the answer right.)
“W can’t be in, because they would knock out both R and V. So RVW must be chosen. And R must be leader (rule 1).”
I assume you mean RVX must be chosen (since W can be with neither R nor V).
Yes that is correct, W can’t be in if we want to keep 3 workers in.
Why are we not able to select Answer: A? If we do not select S, then T would not be selected
T is necessary, not sufficient. Rule 2 is diagrammed as “if S -> T). T can be chosen without S being chosen, but if S is chosen, then T must also be.
“So only RVWX are left to place. We need three of them. W can’t be in, because they would knock out both R and V. So RVW must be chosen. And R must be leader (rule 1).” – Wouldn’t this mean RVX must be chosen if W has to be out?
The setup shown with letters crossed out is wrong, and the following paragraph.
So RV”X” must be chosen