Mary has qualified to become a police officer.

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Mary has qualified to become a police officer. Has Albert qualified to become a police officer?
1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.

AO- B. Need an explanation pls....
Source: — Data Sufficiency |

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by Shalabh's Quants » Fri Apr 27, 2012 5:33 am
amsm25 wrote:Mary has qualified to become a police officer. Has Albert qualified to become a police officer?
1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.

AO- B. Need an explanation pls....
These are implication/Conditional statement in the form of 'If..Then..'

Statement 1...

It is basically 'If P then Q' type implication. 'If P then Q' to be True, it is not necessary that P (Albert qualifies to become a police officer) is true when Q (Mary qualifies to become a police officer) being true.

We know that Q (Mary qualifies to become a police officer) is true, but P (Albert qualifies to become a police officer) can be true/false. Not sufficient.

By analysing non-mathematically, Mary's police officer qualification is not solely defendant on Albert's qualification. Since we know that Mary is already qualified to be police officer, it may occur despite Albert not qualified. hence Albert may/not be qualified. Insuff.

Statement 2...

It is 'If P not then Q not' kind of statement. By similar argument, we can infer that Mary's police officer qualification is solely defendant on Albert's qualification. Since we know that Mary is already qualified to be police officer, hence Albert must be qualified. Suff. Ans B.
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by Brent@GMATPrepNow » Fri Apr 27, 2012 6:19 am
I should point out that the GMAT seldom tests formal logic (deductive) logic. When it does, the concepts tested are very straightforward.

This question requires knowledge of something called the contrapositive, which says:
If we have a statement that says "If A then B," then we can also conclude that it must be the case that "If not B then not A"
This brand of formal logic is out of scope for the GMAT. So, for those students out there who became deeply concerned when they read the question, don't worry. This concept is not required knowledge.

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by ronnie1985 » Fri Apr 27, 2012 7:55 am
Thanks Brent...

Deductions are difficult to comprehend...
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by minhchau1986 » Fri Apr 27, 2012 8:05 am
The answer is B

Using the logical constraints,
If A, then B
So .....if not B, then A

Apply to the problem, we have
Answer 2, if no A, then no M
It means If M is true, then A is true

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by shantanu86 » Fri Apr 27, 2012 6:07 pm
amsm25 wrote:Mary has qualified to become a police officer. Has Albert qualified to become a police officer?
1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.

AO- B. Need an explanation pls....
Its easy..
Lets analyze both-

1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
=> Albert is of lesser caliber than Marry that's why his qualification automatically ensures Mary.

2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.
=> This correctly indicated that Albert is of higher caliber as his disqualification implies Mary's.

Thus, from 2 if Mary qualified Albert has qualified too.
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by Shalabh's Quants » Sat Apr 28, 2012 4:39 am
shantanu86 wrote:
amsm25 wrote:Mary has qualified to become a police officer. Has Albert qualified to become a police officer?
1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.

AO- B. Need an explanation pls....
Its easy..
Lets analyze both-

1)If Albert qualifies to become a police officer, then Mary will qualify to become a police officer.
=> Albert is of lesser caliber than Marry that's why his qualification automatically ensures Mary.

2)If Albert does not qualify to become a police officer, then Mary will not qualify to become a police officer.
=> This correctly indicated that Albert is of higher caliber as his disqualification implies Mary's.

Thus, from 2 if Mary qualified Albert has qualified too.
No, I am afraid that's not the case Shantanu. The statements need not be analysed qualitatively. As Brent pointed out that it is Mathematical/Deductive reasoning question. Discard factual facts to infer.

Even on funny side the statement could be...
'If Messy scores goals then Obama will be re-elected.' There is no co-relation between them.

Well as Brent has pointed out 'this question is out of scope of GMAT'.
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by shantanu86 » Sun Apr 29, 2012 6:11 am
Hi Shalabh,

I'm not too sure if the question is within the scope of GMAT but then I see no reason why it shouldn't be analyzed :)

In GMAT, or any other exam for that matter, one must restrict himself to the purview of information divulged by question.

So, if in GMAT it says-
'If Messy scores goals then Obama will be re-elected.' There is no co-relation between them.
We are ought to believe it irrespective of its factual correlation :)

Thus (for the purposes of GMAT) it concludes

If Obama not reelected => Messy didn't score goals

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Shantanu
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