#7 - Every adult male woolly monkey is larger than even the

[Administrator]

Complete Question Explanation

Must Be True-SN. The correct answer choice is (D)

This stimulus provides the information that every adult male wooley monkey is larger than any female wooley monkey, and that every adult male will dominate any female. If these statements are true, their Contrapositives are also true: no female is larger than any adult male, and no female will dominate any adult male. This is often valuable information to consider in a Must Be True question when the given statements are not easily combined to form a conclusion.

Answer choice (A): The stimulus suggests that size and gender are likely factors, but there is not enough information to prove the claim that size is the primary determinate of relations of dominance.

Answer choice (B): The only information known about the dominance by male wooley monkeys deals with adult males. No claim can be made about the dominance of adolescent males.

Answer choice (C): This is not necessarily true because it is not known whether the male is an adult. Again, a claim can be made about the dominance of a male only if that male is known to be an adult.

Answer choice (D): This is the correct answer choice. The Contrapositive of the second statement is that no female will dominate any adult male. If this is true, the only way a female could dominate a male would be if that male were not an adult.

Answer choice (E): This statement contradicts the claim in the stimulus that any adult male will dominate any female. It does not seem to matter whether the female is an adult.

[S77]

Stimulus: Every adult male woolly monkey is larger than even the largest female woolly monkey. In colonies of woolly monkeys, any adult male will dominate any female.

Question Stem: If the statements above are true, which one of the following must on the basis of them be true of woolly monkeys in colonies?

I diagrammed the premises as follows:

Adult Male --> larger than largest Female
Contrapositive: if you are NOT larger than the largest female, you CANNOT be an Adult Male

Adult Male --> dominate any female
Contrapositive: If you do NOT dominate any female, you CANNOT be an Adult Male

Are these diagrams correct? Could they be improved? I am looking for feedback about how to diagram this question and precisely WHY the correct answer D follows from these diagrams.

Any help would be much appreciated!

Thanks!

[BethRibet]

Hi S77,

Thanks for your query!
Your diagrams are entirely correct. The only thing I would suggest in practice (on the test) is to try to abbreviate, as you won't have time to write them out in this much specificity.

As to answer choice D, the phrasing "If a female woolly monkey dominates a male of the species" is roughly equivalent to (or at least consistent with) your second contrapositive: "If you do NOT dominate any female". In both, a male does not dominate a female.
The second part of D: "the dominated male monkey is not an adult.", fits your phrasing: "you CANNOT be an Adult Male".

Hope this helps clarify!

Beth

[mlhousto]

I'm going to apologise in advance, but this question has a few questions wrapped up in it, too. Sorry!

Okay, I'm having a very difficult time with this entire section. My instructor recommended reviewing conditional reasoning for our next lesson, and i'm just having a difficult time diagramming the statements in general. I seem to always have to revert the diagram back into a sentence to make sense of it. I know that's not possible on the real LSAT because of time constraints, any tips?

For instance, in question 4.

My original diagram was

AM F

(If adult male, will dominate any female)

Not F Not AM

(if female is not dominated, then it is not by an adult male)

Also, I'm not sure how to diagram the first part of the stimulus, either/ how it works with the other information given to form an answer. I still picked answer choice D using only the second sentence.

Question 6

DG WP
If the dog growled, then it was a white poodle.
Not WP No
If it was not a white poodle, the dog didn't growl.

(Also, I'm not really understanding how C is the answer.)

[Andrew Ash]

Hi M,

You've hit the nail right on the head - conditionality is a difficult topic to master, and it takes lots of practice. If it's any consolation, though, you're doing a great job already - in fact, your diagrams for both questions is perfect!

Try to stick with it until diagramming has become second nature to you. It's not just that using English takes more time; it's less accurate, too. Once you have these skills down pat, you'll have perfect accuracy on conditional questions, and you'll save time and mental energy. It's absolutely worth it.

One of the best ways to review conditionality is to check out the recap of lesson 2, in the lesson 2 supplementary materials on the Online Student Center. It's by Jon Denning and Dave Killoran, and it's an excellent review for these topics.

Now, on to the specific questions you mentioned:

Lesson 2-62, question 4: The first sentence actually doesn't come into play at all, which is why you correctly picked answer choice (D). If we wanted to diagram it as an exercise, though, it would look like this:

Adult male Larger than all females

As you pointed out, though, answer choice (D) is a contrapositive of the second sentence, which is why it's the correct answer.

Lesson 2-63, question 6: As your contrapositive shows, if it wasn't a white poodle, it didn't growl. Being a white poodle is "necessary" for growling. So any gray dogs that might have been at the show definitely didn't growl - which is why answer choice (C) is correct.

We actually have two conditional statements here:

White poodle Growled at Elena
Growled at Elena White poodle

Since these are reversals of each other, this is an "if and only if" situation, which is most easily represented by a double arrow:

White poodle Growled at Elena

You can review double arrows on page 2-16.

I hope this helps!

Best,
Andrew

[mlhousto]

Ah thank you so much, Ash! Especially for the last answer. I had completely blanked on if and only if statements signalling the double arrow.

But I'll make certain to check out the link, too. Is there anywhere I can find the in-depth explanations to the conditional problems from lesson 2?

[Morgan O'Donnell]

Hi mlhousto-

The explanations for the Conditional Reasoning Homework (and all other LR Homework) for Lesson 2 can be found in your Online Student Center under "Lessons and Homework Supplements"--> "Lesson 2". The very first box on that page is called "Explanations: Lesson 2". On page 2-4 of that document, you will find the beginning of those lengthy explanations. If you still have any questions about them, please post them on the Forum and we can help you out!

Let me know if you have any questions!

Thanks,
Morgan O'Donnell
PowerScore Test Prep

[LearntheLSAT]

Hello!

I think I understand the logic, but I want to clarify on how D is the correct answer. I diagramed it as such:

AAM -> AFM

(Any Adult Male -> Any Female Monkey)

Contra: No AFM -> No AAM

(No Female Monkey will dominate Any Adult Monkey)

I chose B originally because I missed the adolescent part. If it had said adult monkey, would this be a safe answer?

Also, is D correct because it is a restatement of the contrapositive? (almost making it positive, which is why I believe I was confused by this answer choice upon first glance because it mentioned female monkey's positively and not in a negation form) I thought it to be a mistaken reversal. Can you explain a bit how they sneakily made the contrapositive positive without negating its meaning?

[James Finch]

Hi Learn the LSAT,

Technically yes, if (B) was referring to adult male woolly monkeys instead of adolescents then it would be correct, but also extremely close to a restatement of the second sentence of the stimulus, which along with the "some" scope would make it an unlikely answer to show up.

(D) is a much more common answer to see, especially on early questions, as the LSAT loves to test contrapositives or chain inferences on Must Be True questions. (D) is indeed the contrapositive of the second sentence of the stimulus:

Adult Male Dominate Female

Dominate Female Adult Male

Hope this clears things up!

[dcruz3]

Hi!
After reading the replies I think I can agree that D is the best answer out of the rest, but I initially didn't choose it, and am still having difficulty choosing it wholeheartedly now because I thought we weren't allowed to infer that a female not being dominated is equivalent to a female dominating a male (what if she is just not dominated but isn't able to dominate either, a tie of sorts) because this is a must be true not could be true?

My diagram:

adult male larger than any female
CP: not larger than any female not adult male

any adult male dominate any female
CP: not dominate any female not adult male

(Am I wrong to think we have to think in terms of logical opposite? For example, dominate any female's negation is not dominate any female and can't be female dominates male.)

Thanks!