Question 48 of 161EasyMCQ
Let R={(3,3),(6,6),(9,9),(12,12),(6,12), (3,9),(3,12),(3,6)} be a relation on the set A={3,6,9,12}. The relation is :
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Official solution
We have to examine whether the relation R satisfies the properties of reflexivity, symmetry, and transitivity.
Relation R : R={(3,3),(6,6),(9,9),(12,12),(6,12), (3,9),(3,12),(3,6)} on set A={3,6,9,12}.
We will evaluate each of the three properties :
Reflexivity : A relation is reflexive if all elements in the set are related to themselves. Here, (3,3), (6,6), (9,9), and (12,12) are all present in R, so R is reflexive.
Symmetry : A relation is symmetric if for every pair (a,b) in the relation, the pair (b,a) is also in the relation. In R, we have pairs such as (6,12) and (3,6), but their corresponding reverse pairs (12,6) and (6,3) are not in R, so R is not symmetric.
Transitivity : A relation is transitive if for every pair of pairs ((a,b), (b,c)) in the relation, the pair (a,c) is also in the relation. For the pairs (3,6) and (6,12) in R, we have (3,12) in R, and for the pairs (3,6) and (6,6) in R, we also have (3,6) in R. Therefore, R is transitive.
Therefore, the relation R is reflexive and transitive, but not symmetric.
So, the correct answer is Option D : R is reflexive and transitive only.
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