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PrepTest 78, Game 1, Question 2


The second question of PT 78, says if T is project leader and W is project number, then the third project member must be either blank. Now this is a local question because we have new information, if the new information is T is project leader, and W is project member. So, I wanna draw a local diagram on my scratch paper, and I wanna make T the project leader and I wanna put W in the in group.

And I don't wanna just go to the answer choices, I want to then go to my rules and see what other deductions we can make from applying our rules. Based on the first rule, we know that if Q or R in, they have to be project leaders, so if somebody else's project leader T, that means you can't put Q in and you can't put R in. If we tried to put one of these letters in, then we'd have a conflict between them being project leader and T being project leader.

The next rule that triggers is rule number three, because if W is in that means you can't see R and you can't see V. So since W is in, that means R is out and R is already out based on rule number one, but we also have to put V out. And now at this point notice that we've already handled the Q, the R, the T, the W, and the V, the only letters left are the S and the X.

And right now either one of these letters could be in or out, you could put S in or you could put X in, and you could put S out or you could put X out. Now if you're thinking doesn't affect that T in, mean that S also has to be in, that's probably because you're reading rule number two backwards. Rule number two means, if S is selected then T is selected, but this arrow only goes one way, just because we start off knowing that T is in that doesn't necessarily mean that S is in.

T is allowed to be a project member without S, so that's why we could have X in we don't have to have S in. So now we've done the work on this question, the question is asking the third project member must be either blank. Well, we have already figured out the third project member is either S or X, that's why D is going to be our answer.

Answer choice A is wrong because you can have X in you don't have to have S or S. B is wrong because you could have the third member being S, it doesn't have to be Q or X. C is wrong because the third member actually cannot be R or V, remember W in means R or V is out. And E is wrong because the third member, it could be S, it doesn't have to be one of V or X.

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