PT11.S2. Q12 - in the centerville botanical gardens

Waiting For Grey DayWaiting For Grey Day Alum Member
edited October 2017 in Logical Reasoning 323 karma

Hi!

I've spent about 30 minutes trying to figure out this question but it seems I've hit a wall. I was able to eliminate (A) and (D) quickly but had a hard time understanding what the "youngest" "oldest" phrases were referring to. I ultimately went with (C), considering that there is a majority of S that is older than D (which, I thought, leaves some of S that is not older and/or is the same age as D). But I was taken back to find out the answer if (E). I tried to wrap my head around why (C) or (B) is wrong and why (E) is right but I wasn't able to get far.

It would be really helpful if someone could help me with this question.

Thank you so much in advance! :)

Comments

  • AllezAllez21AllezAllez21 Legacy Member Inactive Sage Inactive ⭐
    1917 karma

    I think it helps to really narrow in on the MUST be true nature of this question. That's a very narrow acceptable answer, given the limited information presented in the stimulus. We only know what's presented in the stimulus, so we should keep in mind that anything not explicitly excluded by the stimulus could be true or could be false.

    With that, moving on to the answer choices. To eliminate an answer as wrong, we need to prove that it could be false.

    For answer B, it could be true, but it doesn't have to be true. Let's just say that half of the sycamores are 100 years old, half are 50 years old. Maples are all 75 years old. This satisfies the stimulus. Now, all dogwoods must be younger than maples. So let's call them all 1 year old. Thus, NO dogwoods are as old as the youngest sycamores.

    For answer C, again it could be true using the same scenario above. The negated version is basically, "All sycamores are at least as old as dogwoods."

    For answer E, it must be true. To negate this answer, we would need to prove that all sycamore trees are at least as old as the youngest tulips. But let's think about that. We know that there are at least some sycamores that are younger than maples. Yet, EVERY tulip is older than EVERY maple. Put some numbers to it. All maples are 10 years old. Every tulip therefore must be 11 years or older (roughly). Yet, we also know that there must be some sycamores younger than 10. How can such trees be both younger than 10 and more than 11? It doesn't work. E must be true.

  • BinghamtonDaveBinghamtonDave Alum Member 🍌🍌
    8673 karma

    I have this question in a notebook I am compiling that I look at daily. Each question I put in the notebook has something unique to it that I keep with me as a quick 2 second reminder on future questions. This question is a bit difficult because the first time I read it, my mind skipped over the phrase "a majority, but not all." In my experience, this is a seldom used construction of grammar on the LSAT. I would say 9.9 times out of 10 "a majority" on the LSAT signifies "most" and most includes the possibilityof all. By using the "majority, but not all" construction, the test writers have explicitly delineated the boundaries of the relationship. To illustrate precisely what we have ben told for this question, I have created the following visual aide.

    The red area of the chart is the first sentence along with our key signifying that "to the right of" is older. Every tulip is older than every maple
    The blue area of the chart is our second sentence: "most but not all" sycamores are older than any of the maples.
    And finally the black pen area is every dogwoods is younger than all maples.

    pt10 photo IMG_0090_zpssrcbekba.jpg

    Now, this question contains another layer of difficulty: that of set and superset. If I tell you: all grizzly bears weigh more than all hummingbirds, implicitly I am also telling you that all newborn grizzly bears weigh more than all adult hummingbirds. I am also telling you all grizzly bears that were born on October 18th weigh more than every hummingbirds born on April 9th. Basically, any and all modifier I want to add is contained under the superset of "all." They did that with this question.

    (E)tells us that some sycamores are younger than the youngest tulip. (E) posits that some Ss are younger than a subset of the T superset. Some Ss are younger than the Ts that have autumn colored leaves. Some Ss are younger than the Ts that have branches that are a nuisance to the power grid at the Centerville Botanical Gardens. It doesn't matter what modifier we use for the T subset. This is the relationship outlined in green below.

    photo IMG_0091_zpsjnqy9wgy.jpg

    I should note in passing here that this all works because we have confined our sampling of trees to a specific domain: that of Centerville Gardens. All of what is true here MBT when we confine it to that domain.

    One of the sages on this site posted recently about upcoming workshops. One of them will be on this idea of set-superset.

    David

  • Regis_Phalange63Regis_Phalange63 Alum Member
    1058 karma

    @BinghamtonDave said:
    I have this question in a notebook I am compiling that I look at daily. Each question I put in the notebook has something unique to it that I keep with me as a quick 2 second reminder on future questions. This question is a bit difficult because the first time I read it, my mind skipped over the phrase "a majority, but not all." In my experience, this is a seldom used construction of grammar on the LSAT. I would say 9.9 times out of 10 "a majority" on the LSAT signifies "most" and most includes the possibilityof all. By using the "majority, but not all" construction, the test writers have explicitly delineated the boundaries of the relationship. To illustrate precisely what we have ben told for this question, I have created the following visual aide.

    The red area of the chart is the first sentence along with our key signifying that "to the right of" is older. Every tulip is older than every maple
    The blue area of the chart is our second sentence: "most but not all" sycamores are older than any of the maples.
    And finally the black pen area is every dogwoods is younger than all maples.

    pt10 photo IMG_0090_zpssrcbekba.jpg

    Now, this question contains another layer of difficulty: that of set and superset. If I tell you: all grizzly bears weigh more than all hummingbirds, implicitly I am also telling you that all newborn grizzly bears weigh more than all adult hummingbirds. I am also telling you all grizzly bears that were born on October 18th weigh more than every hummingbirds born on April 9th. Basically, any and all modifier I want to add is contained under the superset of "all." They did that with this question.

    (E)tells us that some sycamores are younger than the youngest tulip. (E) posits that some Ss are younger than a subset of the T superset. Some Ss are younger than the Ts that have autumn colored leaves. Some Ss are younger than the Ts that have branches that are a nuisance to the power grid at the Centerville Botanical Gardens. It doesn't matter what modifier we use for the T subset. This is the relationship outlined in green below.

    photo IMG_0091_zpsjnqy9wgy.jpg

    I should note in passing here that this all works because we have confined our sampling of trees to a specific domain: that of Centerville Gardens. All of what is true here MBT when we confine it to that domain.

    One of the sages on this site posted recently about upcoming workshops. One of them will be on this idea of set-superset.

    David

    Hello David,
    I've just revisited this question after bombing the IDENTICAL question from PrepTest A.S4.Q24 - In the Hartshorn Building. Since you must've done a lot more recent PTs than I have, do you recall encountering the similar question in later PTs? I find this question to be unique since it's not the same as other ordinary all/some inference questions. I guess I'm curious as to how many similar questions there have been in the history of modern LSAT. So far, I've got two haha.

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