159 comments

  • 3 days ago

    But HOW do we know that the conditional rule applies to ALL vacuum tubes when not ALL vacuums meet the sufficient condition to trigger the rule?

    And I don't see how the final sentence applies to SEVT when they are a unique set with their own quirks: I understand the while superset / subset thing, but I think that tool makes it a little confusing here.

    1
  • Thursday, Feb 05

    Not sure why J.Y. is confused and hung up on A not specifying SE vacuum compared to vacuum tubes in general. The statement that matters here is the one that says "vacuum tubes' maximum current capacity is presently not comparable"

    This the condition that makes A the correct answer, and as you can see, it is not specifying SE vacuum tubes. It is stating that ALL vacuum tubes are not currently comparable..... There is no mistake and no elaborate assumption here

    4
  • Edited Tuesday, Feb 03

    Another one correct LET'S GO

    Quick tip: when practicing MSS and MBT questions, I tell myself “I don’t know” if I can’t reasonably "get" what the question is asking from the stimulus alone. Treat the stimulus like a law or a set of facts that defines a new reality. Once you accept that reality and stop having outside assumptions, many answer choices eliminate themselves and the correct one becomes much more obvious.

    4
  • Edited Friday, Jan 30

    I'm not sure if I mapped this out correctly, but this is how I did it and came to the correct answer.

    Greater Heat resistance AND Comparable to Semi -> Preferable

    The final sentence of the stimulus references "Vacuums", not just "small experimental vacuums".

    Meaning that all vacuums fail to meet the sufficient condition and are therefore not preferable.

    EDIT: Can someone help clarify this for me?

    I read the sentence "Any component...preferable in digital circuits... but only if...." as

    "Any A is B, but only if A is also C"

    Does this translate into

    A and C -> B

    or

    B -> A and C

    1
  • Wednesday, Jan 28

    i got this right but the explanation is so long and confusing? i just said our rule is "preferable for use in digital circuits --> component comparable --> component also comparable to SCs" and then the VC max CC is not comparable to SCs, so it fails the necessary condition

    1
  • Friday, Jan 16

    I got this wrong and was so lost because I missed the word "not" in AC A and interpreted it as a contradiction.

    1
  • Wednesday, Jan 14

    I do not see the difficulty that J.Y. indicates in the video. Small vacuum tubes are a subset of all vacuum tubes. If no vacuum tubes allow the capacity of electrical current that is necessary to make them preferred, then the necessary condition fails, game over answer A. Perhaps J.Y. misread "current" capacity as "heat capacity at present."?

    3
  • Friday, Nov 07 2025

    #help Is it important, at this point in learning, to get the questions correct in the time they expect me to get?

    I'm having a hard time doing the question within the timeframe while using Lawgic. If I use Lawgic my confidence in finding the answer skyrockets, but I take twice the recommended time :(

    1
  • Thursday, Oct 16 2025

    I went above the timeline, more than double, and it was suggested to me to review on BR (figured I got my actual take wrong picking A, but stuck with my answer after re-reading the other options and got it right). This will be a mouthful, but here's how I went about it (feel free to correct if I am mistaken):

    A = Small experimental vacuum tubes

    B = Operating in heat

    C = Semiconductors components fail

    D = Component's comparable to semiconductors in all other categories (like max capacity)

    E = Resistance to heat greater to semiconductors

    F = Preferable to use in digital circuits

    First sentence we can construct: A --> B --> C. OK.

    Second sentence: D AND E --> F, and the reasoning is as follows:

    Any component whose resistance to heat is great to that of semiconductors (E) would be preferable for use in digital circuits (F) [so here we have E --> F], but only if that component (from E) is also comparable to semiconductors in all other categories (like max capacity) (i.e. D); this means that E --> F only if D also happens, hence D AND E --> F).

    Taking the contrapositive of both:

    /C --> /B --> /A } Semiconductor components don't fail --> DOES NOT operate in heat --> IS NOT Small experimental vacuum tubes. OK.

    /F --> /E OR /D. } What does this mean?

    NOT preferable to use in digital circuits --> (NOT resistance to heat greater to semiconductors OR Component's NOT comparable to semiconductors in all other categories (like max capacity)). OK.

    Last sentence says that Vacuum tubes' maximum current capacity is presently not comparable to that of semiconductors. So this is /D. What can we draw from /D (based on what I described)? That if F is false (i.e. /F), then at least one of E or D is False (i.e. either /E or /D) [It’s not that /F causes either /E or /D; it’s that if /F is true, at least one of /E or /D must be true, meaning that knowing we have /F leads us to know we for sure have either /E or /D].

    Option A (in the Answer) tells us that "Vacuum tubes are not now preferable to semiconductors for use in digital circuits" = this is /F that I mentioned. That said, we don't know whether /E occurs (i.e. whether the component DOES NOT have resistance to heat greater to semiconductors), so we can't conclude /E or E.

    Knowing that it is /F --> /E or /D, you can tell that based on the last sentence of the stimulus (i.e. /D), and Option (A) [of the answers] giving you /F, that based on this chain, Option A is the right answer.

    0
  • Tuesday, Oct 07 2025

    Once I re-read the stim probably 20 times and got over the girl math I was doing in my head to make sense of the content, I got the question right :)

    -1
  • Edited Tuesday, Sep 23 2025

    I was glad to see lots of other comments. This question actually seemed really straight forward to me but maybe I'm looking at it wrong?

    I simplified the logic as:

    If (Greater heat resistance) AND (comparable) then preferable

    And we are told that although some vacuum tubes meet the first half of the sufficient condition (Greater heat resistance), all vacuum tubes fail the second required condition (comparable).

    As a result of failing the full sufficient condition, it is insufficient to trigger the necessary condition. In other words, even if a vacuum tube has greater heat resistance, none of them are comparable, therefore none of them are preferrable.

    5
  • Saturday, Sep 20 2025

    I feel like it would've been easier to chalk it up to something like this:

    preferred -> comparable

    Contrapositive: /comparable -> /preferred.

    I spent much longer on this question than I think I should have and I wasn't even really thinking of Lawgic or this theoretical approach when I narrowed it down to A), but it makes so much sense in my head.

    3
  • Saturday, Sep 20 2025

    I came here to disagree with the video like so many of you have. However, did you read the text?

    Here is the text explanation:

    There’s one more sentence in the stimulus.

    However, vacuum tubes’ maximum current capacity is presently not comparable to that of semiconductors.

    The third sentence tells us that all vacuum tubes do not currently have maximum current capacity comparable to semiconductors. So, SEVTs fail the necessary condition, and therefore SEVTs must not be preferable.

    That is the explanation we were looking for in the video that was initially missed by J.Y. It was explained in the text following the video. Obviously, the video needs to be updated, but at least it's there in the text explanation.

    Hopefully this helps.

    1
  • Tuesday, Sep 09 2025

    bro this question rocked my shit for a minute, i literally crossed out all 5 answers and then went back to and realized I was overcomplicating things.

    7
  • Wednesday, Aug 27 2025

    im so cooked i suck at these MBT questions bro

    7
  • Tuesday, Aug 19 2025

    Did anyone else base their answer on the "not now preferable" and "presently not comparable" parts of this argument? I follow the VT and SEVT distinctions just fine, and during review, I can understand, but I was having some trouble during the actual drill because I thought that those two made a connection. Do you think this follows logically?

    0
  • Sunday, Aug 10 2025

    No I think it's cuz at the end it says "[all] vacuum tubes' maximum current capacity is presently not comparable to that of semi-conductors," and that disqualifies all vacuum tubes regardless of whether their resistance to heat is greater.

    7
  • Friday, Jul 25 2025

    You can throw away the heat resistance, all that matters is that vacuum tubes don't have comparable max current capacity and that immediately disqualifies them for digital circuits. Easy point.

    5
  • Wednesday, Jul 23 2025

    Got this one in under a minute!

    5
  • Tuesday, Jul 01 2025

    Got this one right on the first attempt! Slowing down helped me a lot. E was tempting because it was my "ideal answer," but learning not to choose the ideal answer with the right one.

    2
  • Friday, Jun 27 2025

    I have to disagree with JY on why A is correct here. I got this right and am confident A must be true because of the only if statement. We know that only if a component (in which we refer to any component) is comparable in ALL other significant respects to semiconductors can it be preferable to a semiconductor in general. We are further told one of these significant respects is maximum current capacity. In the next sentence we learn that vacuum tubes (not just se vacuum tubes) do not have comparable maximum current capacities to semiconductors. Since vacuum tubes are failing the necessary condition of being preferable in all other significant respects we can conclude that vacuum tubes are not currently preferable.

    Let me know if there is any flaws in the logic here. Thanks!

    12
  • Monday, Jun 09 2025

    Accidently thought this was a must be false question bc I didn't read the stem. Got A in the blind review afterwards. I gotta slow down!!

    0
  • Wednesday, Jun 04 2025

    I selected the correct answer but it definitely took me more than 3 minutes and rereading and parsing the stimulus 12 times.

    6
  • Saturday, May 31 2025

    I based the "lawgic" of this question on the understanding that small vacuum tubes contained semiconductor components.. oopss

    0
  • Tuesday, May 27 2025

    The small experimental thing doesn’t make sense to me. A seems airtight. By stating that vacuum tubes don't meet the carrying capacity needed to be equivalent to semiconductors, the passage essentially makes the heat tolerance requirement irrelevant - because, even if the larger group of vacuum tubes were heat tolerant, as the small experimental subgroup is stated to be, they wouldn’t meet the other condition needed (carrying capacity). So, we can say that it must be true that they are not an acceptable replacement.

    2

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