A problem with two definitions

[kirilrez]

The first question-




I got the question right and understand the logic behind it, but was confused at first by the words: "most recently".

Do they have to suggest that what they describe happened before at least once?


And the more interesting question for me-



How do we know the street is not a closed shape- a circle where there are no edges- don't they have to tell us that?

Another thing they don't say is if that the families can live together in the same house before the answers, is that what they do on the Lsat too?

Moreover, why don't the other families live together if two of them do - this is also not mentioned in the question prompt.

I got the question right only by assuming the street had to be a straight line?

[timmydoeslsat]

In regards to the first, question, I am not aware of the correct answer, but I would believe the answer is that we can infer that the first humans to enter the Americas was over 7,000 years ago.

The language of most recent land bridge is, as you pointed out, a big factor here.

It does not have to be true that the people that crossed that land bridge did so on the most recent one, perhaps it was the very first land bridge that ever appeared, or the 500th. We cannot infer that.

I think the issue with some of your questions is that you are making your point in a way! You have questions about some these answer choices due to the fact that we would have to make assumptions for them to have a chance of being true. This means we cannot infer it.

However, a bigger takeaway from these games on Manhattan is to get used to the idea of getting an idea of what cannot be inferred.

As in the issue of the next question with the families, we cannot infer that at most four families live on that street. We do not have to assume that this neighborhood is aligned in a linear manner, it could indeed by a circle, we do not know.

We do know this:

H_J

H_K

These blocks are reversible obviously. And, as we learn, these families could live in the same house, such as with J and K both living in the same house and both, at the same time, would have 1 family between them.

So, if J and K do live together...

H_JK

Does that mean at most four? It could be true, but it does not have to be. We could go on down the line for 6,000 spots. We cannot infer a maximum.

However, with the other answer choice, if J and K do not live in the same house, we do know that at least 5 homes are on this street.

We know for a fact we have this:

H_J

We also know that K must have exactly one family live between them and H. Since this conditional has it be the case that J and K cannot be in the same house, we must have this situation occur:

K_H_J

We know of 3 families being placed, with exactly 1 going in each blank spot.

It could be the case that ABCDEF families also all live in K's house as well. It could be true that those hypothetical families live to the west of K, all in a row. We do not know. However, we do know that if J and K are not in the same house, there must be at least 5 families on that street.

[noah]

In regards to the first, question, I am not aware of the correct answer, but I would believe the answer is that we can infer that the first humans to enter the Americas was over 7,000 years ago.

The language of most recent land bridge is, as you pointed out, a big factor here.

It does not have to be true that the people that crossed that land bridge did so on the most recent one, perhaps it was the very first land bridge that ever appeared, or the 500th. We cannot infer that.

I think either way the answer is correct. Humans entered over 7.000 years ago.

I think the issue with some of your questions is that you are making your point in a way! You have questions about some these answer choices due to the fact that we would have to make assumptions for them to have a chance of being true. This means we cannot infer it.

I imagine we have made some mistakes in some of our questions--but in these two questions, I don't see an issue. And, from your responses, it seems like you agree.

However, a bigger takeaway from these games on Manhattan is to get used to the idea of getting an idea of what cannot be inferred.

That is a great thing to take away from Ah-Hah!

I think your explanation for the other problem is spot on.

[zagreus77]

I 'll just take the first. The correct answer is 7,000 years ago because the stimulus says that the first humans crossed a land bridge and the most recent such land bridge appeared 25,000 years ago and disappeared 7,000 years ago. This formulation leaves open the possibility of another land bridge even earlier than 25,000 years ago which humans may have crossed, so we don't know based on this stimulus whether the first humans arrived less than 25,000 years ago.

We do know since there has been no land bridge for 7,000 years and the first humans arrived via land bridge that they definitely arrived more than 7,000 years ago.