No chordates are tracheophytes, and all members of Pteropsida are trac

Its a 30 second question if you use Venn diagrams.

method: (draw as you read)
Draw two circles touching each other but they shouldn't overlap. Label one as C and the other as T. In T, draw a smaller circle and label it as P.
now the conclusion states that no member of P belongs to H.
This can only be possible in two ways. If H lies outside of both the bigger circles,C and T, or H lies inside C.
Now select the answer.

Hello email2vm

I'm glad to help.

ANALYZE THE STIMULUS:

Name:
C = chordates
T = tracheophytes
P = Pteropsida
H = Hominidae.

Argument says:
(1) C # T (No C = T)
(2) P = T (All P = T)
(3) Thus: P # H (No P = H)

If H = C --> P # H. Because If H = C --> H # T (according fact 1), but we also have P = T --> P # H (conclusion)

ANALYZE EACH ANSWER:

(a) All members of the family Hominidae are tracheophytes
Wrong. H = T --> P = H. Hence, wrong.

(b) All members of the family Hominidae are chordates
Correct. H = C --> H # T, but P = T --> H # P. Correct.

(c) All tracheophytes are members of Pteropsida
Wrong. T = P. This is fact #2. Clearly, it is an assumption.

(d) No members of the family Hominidae are chordates
Wrong. What if H # C, but H = T? --> P = H --> Clearly the conclusion P # H is wrong.

(e) No chordates are members of Pteropsida
Wrong. C # P. This is a combination of fact #1 and fact #2. The combination is still a FACT. It is not a hidden statement which is defined as an assumption by GMAT standards.

Hope it helps.

since no C is T,
means H has to be a part of C so that P does not belong to H.

its clear from B.
Hence B. You can draw Venn diagrams for such questions.

OKAY LOGIC IN THE ARGUMENT:

~C--> T
P--> T

Conclusion: ~P--> H

THE MISSING LINK IS EITHER BETWEEN H and T or H and C.

(a) All members of the family Hominidae are tracheophytes--> THIS IS JUST OPPOSITE OF WHAT WE WANT
(b) All members of the family Hominidae are chordates--> CORRECT
(c) All tracheophytes are members of Pteropsida--> OUT OF SCOPE
(d) No members of the family Hominidae are chordates--> OPPOSITE OF WHAT WE WANT
(e) No chordates are members of Pteropsida--> OUT OF SCOPE

HENCE B is correct.

Hope this helps..!!!

Why e is wrong?

CH NOT TR
PT=TR
conclusion PT NOT HO

(e) No chordates are members of Pteropsida
Wrong. C # P. This is a combination of fact #1 and fact #2. The combination is still a FACT. It is not a hidden statement which is defined as an assumption by GMAT standards.


It absolutely makes sense:
1> The premise (assumption) should not be stated fact in the question
2> It should hold true
3> pass negation test

Can u explain why option A is wrong? Even with that we can get the conclusion. I used tick and cross method. I believe both options A and B are good enough for right answers. Please explain me where I am going wrong. Thanks in advance.

Good question
To solve this question we use some numbers

ALL= 100
No= 0
Conclusion: 0P ---> H
Premise: 0C---->T and 100P----> T

(a) IncorrectAll members of the family Hominidae are tracheophytes
100H----> T the nthere is a possibility that few P belong to H.
(b) CorrectAll members of the family Hominidae are chordates
100H-----> C. and 0C ----->T and 100P----> T so there is no chance of overlap
(c) All tracheophytes are members of Pteropsida
(d) No members of the family Hominidae are chordates
(e) No chordates are members of Pteropsida
Similarly we can check for option C, D, and E

Hence B is the answer

Hi abhimahna,

I think this question stem should be : which of the following CAN be an assumption.

Because
The family of H can lie outside both C and T
OR
The family of H can lie inside C
OR
The family of C can lie inside H.

Thank you
Best Regards

(a) All members of the family Hominidae are tracheophytes
(b) All members of the family Hominidae are chordates
(c) All tracheophytes are members of Pteropsida
(d) No members of the family Hominidae are chordates
(e) No chordates are members of Pteropsida


+1 : B

If H = C, then P can't be equal to H as per premise.
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If we draw a Venn diagram, then there are 2 possibilities. 1. H is outside C and T
2. H is inside c. How can B e the answer? Shouldn't the answer be E as it is true in all the cases.

bedi96
I fell for E as well but lingered around B for a long time. Now the question is as follows:


H can lie in 6 ways. Assuming there's an uncommon area(UA)
1. H lies in T and UA
2. H lies altogether in UA
3. H lies in T, C and UA
4. H lies in C and UA
5. H lies in C
6. C lies in H.

Now with all the available choices only B and E make some sense. E can be an inference but not an assumption. Thus, B is answer as per point no. 5.

Answer B.
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