JEE Main 2025MathematicsSets And RelationsSymmetric Transitive And Reflexive PropertieseasyMCQ

JEE Main 2025Sets And Relations Question with Solution

From: JEE Main 2025 (Online) 3rd April Evening Shift

Question

Let . Let R be a relation on defined by if and only if . Let be the number of elements in R . Let and be the minimum number of elements required to be added in R to make it reflexive and symmetric relations, respectively. Then is equal to

Choose an option

Show full solutionCorrect option: B
Correct answer
B12

Step-by-step explanation

To solve the problem, we start by defining the set and the relation on set , where an element is related to (written as ) if and only if .

This leads us to the following pairs in the relation :

For , , so is in .

For , , so is in .

For , , so is in .

For , , so is in .

For , , so is in .

For , , so is in .

Thus, the relation consists of the pairs: , and there are elements in .

Making the Relation Reflexive

A relation is reflexive if every element in the set relates to itself. Therefore, the missing reflexive pairs are:

Adding these three pairs will make the relation reflexive, so .

Making the Relation Symmetric

A relation is symmetric if whenever is in , must also be in . Therefore, the missing symmetric pairs are:

Thus, we need to add these three pairs for symmetry, so .

Finally, we calculate the sum .

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About this question

This is a previous-year question from JEE Main 2025, covering the Sets And Relations chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.