intersection, T, of R and S

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intersection, T, of R and S

by sanju09 » Tue Oct 18, 2011 1:19 am
Let R be the set of all numbers r such that -5 < r < 8. Let S be the set of all numbers s such that
3 < s < 10. The intersection, T, of R and S is the set of all numbers t such that
(A) - 5 < t < 3
(B) - 5 < t < 8
(C) 0 < t < 8
(D) 3 < t < 8
(E) 8 < t < 10
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by shankar.ashwin » Tue Oct 18, 2011 1:29 am
Set R [-4,-3,-2,-1,0,1,2,3,4,5,6,7]
Set S [ 4,5,6,7,8,9]

Intersection [4,5,6,7] Option D

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by Anurag@Gurome » Tue Oct 18, 2011 2:16 am
sanju09 wrote:Let R be the set of all numbers r such that -5 < r < 8. Let S be the set of all numbers s such that 3 < s < 10. The intersection, T, of R and S is the set of all numbers t such that
R : -5 < r < 8
S : 3 < s < 10

T : Intersection of R and S : All t which satisfies both the conditions for R and S

So, T : maximum of both the minimum limits < t < minimum of both the maximum limits
--> T : max[-5, 3] < t < min [8, 10]
--> T : 3 < t < 8

The correct answer is D.
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by neelgandham » Tue Oct 18, 2011 2:38 am
Intersection :
Maximum (minimum value r, minimum value s)< T < Minimum (maximum value r, maximum value s

=> Maximum(-5,3) < T < Minimum(8,10)
=> 3 < T < 8

OA Option D

Note : Union => Minimum (minimum value r, minimum value s)< T < Maximum(maximum value r, maximum value s