Topic: Selective school test (mhs) verbal reasoning questions - Help Please

[simplyme]

I have stumbled on these 2 questions, help would be much appreciated.
:smitten: :smitten:


1. Some Fs are Bs
    All Bs are Cs

Conclusion: I. Some Cs are not Fs
                 II. Some Cs are Fs.
                 III. No C is F.
                 IV. All Fs are Cs.

(a) None Valid
(b) Only I and II valid
(c) Only I, II and IV valid
(d) Only II, III and IV valid
(e) All Valid

>>> I have found only II valid and the answer is (b)



2. Some Ts are Ps
    All Ps are Es

Conclusion: I. All Es are Ps
                 II. All Ts are Ps.
                 III. Some Ts which are not Ps are Es
                 IV. All Es are Ts

(a) All Valid
(b) Only I and II valid
(c) Only III and IV valid
(d) Only IV valid
(e) None of these

>>> I have found only IV valid (d) but the answer is (c)

Thanks guys!!!! :laugh: :laugh:



 

[Russ]

B is correct, draw a venn diagram if it will help you.
Because not all Cs are Bs, it means that not all Cs are Fs (trust me a diagram really helps, doing it in your head sucks)

I don't see how you can do the second one at all, there's no information to connect the two statements

[simplyme]

Thanks Russ, I did draw a Venn diagram but it did not indicate that I is valid.

With regards to Q2 ..sorry it's a typo and I have corrected it already...

Cheers.

[WhoTookMyUsername]

Q1
Some Cs are not Fs as not All Fs are Bs therefore not all Fs are Cs and therefore not all Cs are Fs
Some cs are F as some Fs are Cs


2)
This question is not well written

Some Ts are not Ps, So Some Ts MAY be Es
 Some Ts are Ps
    All Ps are Es


That's what their gunning for.


I never even though about drawing a venn diagram, and i probably would advise against it as the MHS test is run at a very fast pace so drawing a Venn diagram for each of these questions would simply take too long, and i fail at quickly drawing anything

But as Russ said it will allow you to visualise it instead of seeing merely written words.

[lynt.br]

I'm normally pretty crap at these but am I the only one who thinks q2 should be e?

I: we don't have enough information to make that conclusion. We know all P's are E's but we do not know how large the category of E is to conclude all E's are also all P's. E's could also include a hypothetical group F. Thus this is not a valid conclusion.

II: Clearly violates the first line that Some T's are P's.

III: Here is where I have a problem. I do not think you can make this conclusion without knowing the scope of E. There is no given relationship between the T's that are not P's and group E. It is POSSIBLE that E's includes some T's that are not P's, but there is no statement in support of this thus the conclusion is speculation and not valid. All we know for sure is that the only T's which are E's are also those T's which are P's. We do not know enough about the T's that are not P's.

IV: I don't see how this can be valid either. We don't know the scope of E, so E could be comprised entirely of P but could also include things other than P, including things that are not T's. Even if all E's where P's (Which would subsequently make I correct), we don't know the scope of P, meaning E could include P's that are not T's. Again the conclusion is possible but cannot be determined conclusively without further information about the scope of E.

And given that I is listed as not a correct answer, they clearly do not accept 'possible' conclusions as valid conclusions. Hence none are valid.

There is also a problem with drawing venn diagrams. It depends on how you draw the diagram. I've drawn two possible ways I could see it below.

The big difference being in the second diagram, E's only include P's, meaning E's only include T's that are also P's.


I hope I'm making sense. I figure I'm making a mistake in my logic somewhere so I guess I'll see what you guys think of my reasoning?


EDIT:
looking back at q1, I is only correct if you assume C is not identical to F or B. Otherwise imagine a circle, half the circle is B. The whole circle is F. C could be the same half circle as B, the entire circle the same as F or an even bigger circle. In the first two cases, all C's would also be F's.

[Drunk]

Oh god, bad memories just came rushing back
I hated those types of questions