JEE Main 2021 · MathsMultiple choiceSingle correctMediumCalculation

JEE Main 16 March 2021, Shift 2, Maths Q71

Question 71 of 90 in this shift, Maths question 11 of 30, Section A.

Let

A=\{2,3,4,5,\ldots,30\}

and '

\simeq

' be an equivalence relation on

A\times A

, defined by

(a,b)\simeq(c,d)

, if and only if

ad=bc

. Then the number of ordered pairs which satisfy this equivalence relation with ordered pair (4, 3) is equal to :

(1)5
(2)6
(3)7Official answer
(4)8

Official answer

Option 3

NTA final key.

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

Same idea in other shifts

Asked 10× in all

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31 Jan 2024, Shift 1 · Q21Let $A=\{1,2,3,4\}$ and $R=\{(1,2),(2,3),(1,4)\}$ be a relation on A. Let S be the equivalence relation on A such that $R\subset S$ and…MediumNumerical value
27 Jul 2022, Shift 1 · Q1Let $R_1$ and $R_2$ be two relations defined on $\mathbb{R}$ by $a\,R_1\,b \Leftrightarrow ab \ge 0$ and…EasySingle correct
28 Jul 2022, Shift 1 · Q8For $\alpha\in\mathbf{N}$ , consider a relation $R$ on $\mathbf{N}$ given by $R=\{(x,y):3x+\alpha y\text{ is a multiple of }7\}$ . The…MediumSingle correct
28 Jun 2022, Shift 2 · Q1Let $R_1 = \{(a, b) \in \mathbf{N}\times\mathbf{N} : |a-b| \leq 13\}$ and…EasySingle correct
29 Jun 2022, Shift 1 · Q11Let a set $A = A_1 \cup A_2 \cup \ldots \cup A_k$ , where $A_i \cap A_j = \phi$ for $i \ne j$ , $1 \le i, j \le k$ . Define the relation R…EasySingle correct
26 Feb 2021, Shift 1 · Q72Let $R=\{(P, Q)\mid P$ and $Q$ are at the same distance from the origin $\}$ be a relation, then the equivalence class of $(1, -1)$ is the…EasySingle correct

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 108 of the 174 JEE Main shifts held from 2017 to 2026.