critical reasoning problem

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critical reasoning problem

by arifaisal123 » Sat Oct 08, 2011 7:32 am
Department stores range from two to eight floors in height .If a store has more than three floors, it has an elevator.
If the statements above are true, which of the following must also be true?
a. Second floors do not have elevators
b. Seventh floors have elevators
c. Only floors above the third floors have elevators
d. All floors may be reached by elevators
e. Some two-floor department stores do not have elevators

explain in details pls
Source: — Critical Reasoning |

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by GmatKiss » Sat Oct 08, 2011 8:10 am
IMO: E

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by parul9 » Sat Oct 08, 2011 8:30 am
I think its E.

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by GmatKiss » Sat Oct 08, 2011 8:47 am
GmatKiss wrote:IMO: E
and i guess this is not a valid GMAT question!

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by arifaisal123 » Sat Oct 08, 2011 10:03 am
why is it not valid?? btw its in the barrons how to prepare for the GMAT

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by gmatblood » Sat Oct 08, 2011 10:41 am
arifaisal123 wrote:why is it not valid?? btw its in the barrons how to prepare for the GMAT
ok What is OA?
Barrons!!!!!!! very skeptical with it for GMAT

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by gmatclubmember » Sat Oct 08, 2011 11:11 am
I will go with B.
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by arifaisal123 » Sat Oct 08, 2011 6:11 pm
explain y B and not E

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by gmatclubmember » Sun Oct 09, 2011 2:04 am
E is not true. If the departmental store is 2 floor then it WONT have an elevator. So 'some' in the option is incorrect.
correct E option would look like "All 2 floor department stores do not have elevators"
'2 floor department store' is different from the 'second floor of some department store'.
First says that department store is Necessarily of 2 floors while the second one says that the department store may or may not go beyond 2nd floor.

B is always going to hold good. Any departmental store with 4 or more floor will have the elevator.
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by 786 » Sun Oct 09, 2011 3:22 am
Should be B !

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by Geva@EconomistGMAT » Sun Oct 09, 2011 6:33 am
gmatclubmember wrote:E is not true. If the departmental store is 2 floor then it WONT have an elevator. So 'some' in the option is incorrect.
correct E option would look like "All 2 floor department stores do not have elevators"
'2 floor department store' is different from the 'second floor of some department store'.
First says that department store is Necessarily of 2 floors while the second one says that the department store may or may not go beyond 2nd floor.

B is always going to hold good. Any departmental store with 4 or more floor will have the elevator.
I agree with you that the answer is B for the reason you specify, but disagree with the analysis of E. All that argument tells us is that if >3 floors -> Have elevators. This tells us NOTHING about 2-3 floors - if we go by the rule above, these MAY or MAY NOT have elevators - we simply do not know. The only thing that we know is that if the store has more than 3 floors (for example, a 7th floor), then it MUST have an elevator. So B is right, and E is eliminated because we simply do not know - some 2 level stores may have elevators, or all, or none. We do not have that information.
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by Geva@EconomistGMAT » Sun Oct 09, 2011 6:36 am
GmatKiss wrote:
GmatKiss wrote:IMO: E
and i guess this is not a valid GMAT question!
And yes, this is more LSAT than GMAT - the GMAT tends to stay away from formal logic If A-> then B type questions.
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