Let $A=\{2,3,6,7\}$ and $B=\{4,5,6,8\}$. Let R be a relation defined on $A\times B$ by $(a_1,b_1)\,R\,(a_2,b_2)$ if and only if $a_1+a_2=b_1+b_2$. Then the number of elements in R is ________.

JEE Main 2024 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 9 April 2024, Shift 1, Maths Q21

Question 21 of 90 in this shift, Maths question 21 of 30, Section B.

Let

A=\{2,3,6,7\}

and

B=\{4,5,6,8\}

. Let R be a relation defined on

A\times B

(a_1,b_1)\,R\,(a_2,b_2)

if and only if

a_1+a_2=b_1+b_2

. Then the number of elements in R is ________.

Official answer

NTA final key.

Chapter: Relations and Functions
Topic: Sets and Relations
Idea tested: Counting Relations

Same idea in other shifts

Asked 7× in all

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30 Jan 2024, Shift 2 · Q21The number of symmetric relations defined on the set $\{1, 2, 3, 4\}$ which are not reflexive is ________.MediumNumerical value
6 Apr 2023, Shift 1 · Q21Let $A=\{1,2,3,4,\ldots,10\}$ and $B=\{0,1,2,3,4\}$ . The number of elements in the relation…MediumNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.