LSAT-identify and match the flaw

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LSAT-identify and match the flaw

by gmatnmein2010 » Tue Feb 16, 2010 9:14 pm
Bank deposits are credited on the date of the transaction only when they are made before 3.pm. Alicia knows that the bank deposit was made before 3 p.m . So, Alicia knows that the bank deposit was credited on the date of the transaction.


Which one of the following exhibits both of the logical flaws exhibited by the argument above?

(A) Journalists are the only ones who will be permitted to ask questions at the press conference. Since Marjorie is a journalist, she will be permitted to ask questions.

(B) We know that Patrice works only on Thursday. Today is Thursday, so it follows that Patrice is working today.

(C) It is clear that George knows he will be promoted to shift supervisor, because George will be promoted to shift supervisor only if Helen resigns, and George knows Helen will resign.

(D) John believes that 4 is a prime number and that 4 is divisible by 2. Hence John believes that there is a prime number divisible by 2.

(E) Pat wants to become a social worker. It is well known that social workers are poorly paid. Pat apparently wants to be poorly paid.

the OA as per the set is C
Source: — Critical Reasoning |

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by money9111 » Tue Feb 16, 2010 9:34 pm
this was interesting.. definitely wont see this on the GMAT but it was fun to try... i didn't see any flaws in the original statement though lol.... i chose A though... can you tell me why it's B?
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by thephoenix » Tue Feb 16, 2010 11:13 pm
tough one

passage says Bank deposits are credited on the date of the transaction only when they are made before 3.pm.

this means that no deposit made AFTER 3 pm will be credited but that also means All of the deposits made BEFORE 3pm DO NOT have to be credited for sure.

hence there is a flaw

now
Alicia knows that the bank deposit was made before 3 p.m . So, Alicia knows that the bank deposit was credited on the date of the transaction.

here the only thing whic luks tricky is that alicia nows that the bank deposit was made before 3 p.m, but nothing is mentioned about her being known about the rule of bank that no deposit made AFTER 3 pm will be credited.

If she doesn't know the rule above , she wouldn't be able to make this logical inference.
so she is making an assumption

hence there is a flaw

hence the argument contains two flaws

now we need to match it

a)ournalists are the only ones who get to ask questions, but that doesn't mean every journalist gets to ask questions..matches flaw no. 1 , however we need Marjorie to assume she'd be permitted to ask questions.
incorrect

2)incorrect does not match the 2nd flaw

3) correct

4) no flaw

5) 1st flaw is not there