maths-dse

[ritu]

now this is a very strange question that i have tried to do like hell...but to no avail...so pls help...
CONSIDER A SOCIETY CONSISTING OF INDIVIDUALS.THESE INDIVIDUALS MAY BELONG TO VARIOUS SETS CALLED CLUBS AND TRIBES.THE COLLECTION OF OF CLUBS AND TRIBES SATISFY THE FOLLOWING RULES:
THE ENTIRE SOCIETY IS A TRIBE.

THE EMPTY SUBSET OF SOCIETY IS ALSO A TRIBE.

GIVEN ANY COLLECTION OF TRIBES,THE SET OF INDIVIDUALS WHO BELONG TO EACH TRIBE IN THAT COLLECTION IS ALSO A TRIBE.

GIVEN ANY TWO TRIBES THE SET OF INDIVIDUALS WHO BELONG TO ATLEAST ONE OF THESE TRIBES IS ALSO A TRIBE.

A SET OF INDIVIDUALS  IS CALLED A CLUB IF ND ONLY IF THE SET OF INDIVIDUALS NOT IN IT CONSTITUTE A TRIBE.

1.THE INTERSECTION OF TRIBES IS NECESSARILY
A.CLUB
B.TRIBE
C.NOT A CLUB
D.NOT A TRIBE

2.UNION OF A COLLECTION OF CLUBS IS NECESSARILY
A.NOT A CLUB
B.NOT A TRIBE
C.A CLUB
D.A TRIBE

3.WHICH OF THE FOLLOWING STATESMENT IS ESSARILY TRUE
A.SET OF INDIVIDUALS CANNOT BE A TRIBE AND A CLUB
B.THERE ARE ATLEAST TWO SETS OF INDIVIDUALS THAT ARE BOTH A CLUB AND A TRIBE
C.UNION OF A CLUB AND TRIBE IS A TRIBE
D.INTERSECTION OF CLUB ND TRIBE IS A CLUB

[anon_econ]

Q1. (b)..u can get it directly from the 3rd rule.
Q2. Say the clubs are C1,C2,..Cn. Their union is a club iff U-(C1 U C2 U..U Cn) is a tribe. But this is just the intersection of the tribes U-C1, U-C2,...,U-Cn. The intersection of tribes is a tribe, so the answer is (c).
Q3. (b)- the 2 sets are the entire society and the empty set.

[Anakin Skywalker]

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[Anakin Skywalker]

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[The Villain]

Same doubt...this question keeps turning up...!!!!Guys pls help..!!

[Shefali]

Pls explain ...no idea on how to even begin with it

[Akshay Jain]

[Akshay Jain]

*M not quite sure of my explanation of #3rd question......

[Anakin Skywalker]

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