PrepTest 78, Game 3, Question 15
Transcript
This is question 15, which is the fourth question in PT 78, game 3. And it's a global question asking which letter cannot be immediately before V. So, which letter could never be the one that is immediately before V? Well, let's take a look, answer choice A says H. And if we look at our setup here, you'll notice that H in the first version of our OR split, in the first version, H has actually has to come after V.
So it can't come immediately before V in this world. And in the H before T before V world, there's a T that's always gonna get in between the H and the V. So even though H could come before V, it's never gonna come immediately before V like this. That means A is our answer H.
This question is entirely dependent on our understanding of the last rule which you remember means T is earlier than H or T is earlier than V, but not both. So that means if you're in the T before H world, you can't have T before V, that puts V before T. If you're in the T before V world, you can't see T before H, and that puts H before T.
And you can see in both of these worlds, no matter which world we're in, H is not gonna go right before V. Now, let's talk about why the other answers are wrong, B says L, but L could go immediately before V in the second world over here because the order could be LV at the very end, and then it could be H, T, S, M. This is something that is consistent with all of the rules and shows that L could be right before V.
Answer choice C says M, and M could be immediately before V. Again, that could happen in this world over here. This is an order that works, H, T, S, L, M, V. Answer choice C says M, and M could go immediately before V in this world over here. For example, you could have and L and then an S and then M, V, T, H.
So there, M is right before V, that proves C is wrong. And you also know that S could go immediately before V because in this order over here, we didn't have to put the M in 3 and the V in 4. It could have been the other way around with V in 3, and M in 4. So S can go right before V, that proves D is wrong. And finally, E says T but if we're in this world, you could put T immediately before V and it would look like this.
You could have H, S, M, L, followed by T and V. This doesn't violate any rules and proves that T could go right before V.
Read full transcriptSo it can't come immediately before V in this world. And in the H before T before V world, there's a T that's always gonna get in between the H and the V. So even though H could come before V, it's never gonna come immediately before V like this. That means A is our answer H.
This question is entirely dependent on our understanding of the last rule which you remember means T is earlier than H or T is earlier than V, but not both. So that means if you're in the T before H world, you can't have T before V, that puts V before T. If you're in the T before V world, you can't see T before H, and that puts H before T.
And you can see in both of these worlds, no matter which world we're in, H is not gonna go right before V. Now, let's talk about why the other answers are wrong, B says L, but L could go immediately before V in the second world over here because the order could be LV at the very end, and then it could be H, T, S, M. This is something that is consistent with all of the rules and shows that L could be right before V.
Answer choice C says M, and M could be immediately before V. Again, that could happen in this world over here. This is an order that works, H, T, S, L, M, V. Answer choice C says M, and M could go immediately before V in this world over here. For example, you could have and L and then an S and then M, V, T, H.
So there, M is right before V, that proves C is wrong. And you also know that S could go immediately before V because in this order over here, we didn't have to put the M in 3 and the V in 4. It could have been the other way around with V in 3, and M in 4. So S can go right before V, that proves D is wrong. And finally, E says T but if we're in this world, you could put T immediately before V and it would look like this.
You could have H, S, M, L, followed by T and V. This doesn't violate any rules and proves that T could go right before V.
