Page 1
JEE Main Previous Year Questions (2021-2026):
Sets, Relations and Functions
(January 2026)
Sets, Relations
Q1: Let R be a relation defined on the set {1, 2, 3, 4} × {1, 2, 3, 4} by
R = {((a, b), (c, d)) : 2 a + 3 b = 3 c + 4 d }.
Then the number of elements in R is
(a) 6
(b) 15
(c) 12
(d) 18
Ans: (c)
Sol:
let A = {1, 2, 3, 4}
R is defined on A × A such that since
R = {((a, b), (c, d)) : 2a + 3b = 3c + 4d}
since a , b , c , d ? A
Page 2
JEE Main Previous Year Questions (2021-2026):
Sets, Relations and Functions
(January 2026)
Sets, Relations
Q1: Let R be a relation defined on the set {1, 2, 3, 4} × {1, 2, 3, 4} by
R = {((a, b), (c, d)) : 2 a + 3 b = 3 c + 4 d }.
Then the number of elements in R is
(a) 6
(b) 15
(c) 12
(d) 18
Ans: (c)
Sol:
let A = {1, 2, 3, 4}
R is defined on A × A such that since
R = {((a, b), (c, d)) : 2a + 3b = 3c + 4d}
since a , b , c , d ? A
Let possible values of 2a + 3b = L1 and possible values of 3c + 4d = L2
Common values of Common values of 2a + 3b = 3c + 4d
7, 10, 11, 13, 14, 15, 16, 17, 18, 20
value 7, 10, 13, 15, 16, 17, 18, 20
occurs 1 time in L1 and 1 time in L2
e.g value 7 occurs 1 time in L1 & 1 time in L2 total = 1 × 1 = 1
so, total number of these types of elements in R = 8 --- (1)
value 11 and 14 occurs 2 times in L1 and 1 time in L2
Page 3
JEE Main Previous Year Questions (2021-2026):
Sets, Relations and Functions
(January 2026)
Sets, Relations
Q1: Let R be a relation defined on the set {1, 2, 3, 4} × {1, 2, 3, 4} by
R = {((a, b), (c, d)) : 2 a + 3 b = 3 c + 4 d }.
Then the number of elements in R is
(a) 6
(b) 15
(c) 12
(d) 18
Ans: (c)
Sol:
let A = {1, 2, 3, 4}
R is defined on A × A such that since
R = {((a, b), (c, d)) : 2a + 3b = 3c + 4d}
since a , b , c , d ? A
Let possible values of 2a + 3b = L1 and possible values of 3c + 4d = L2
Common values of Common values of 2a + 3b = 3c + 4d
7, 10, 11, 13, 14, 15, 16, 17, 18, 20
value 7, 10, 13, 15, 16, 17, 18, 20
occurs 1 time in L1 and 1 time in L2
e.g value 7 occurs 1 time in L1 & 1 time in L2 total = 1 × 1 = 1
so, total number of these types of elements in R = 8 --- (1)
value 11 and 14 occurs 2 times in L1 and 1 time in L2
e.g value 11 occurs 2 time in L1 & 1 time in L2 total
elements in R is 2 × 1 = 2
so total number these type of elements = 2 + 2 = 4 --- (2)
total number of elements in R = 8+4 = 12
Q2: Consider two sets A = {x ? Z : | (| x - 3| - 3) | = 1} and
Then the number of onto functions f : A ? B is equal to :
(a) 32
(b) 81
(c) 79
(d) 62
Ans: (d)
Sol:
Page 4
JEE Main Previous Year Questions (2021-2026):
Sets, Relations and Functions
(January 2026)
Sets, Relations
Q1: Let R be a relation defined on the set {1, 2, 3, 4} × {1, 2, 3, 4} by
R = {((a, b), (c, d)) : 2 a + 3 b = 3 c + 4 d }.
Then the number of elements in R is
(a) 6
(b) 15
(c) 12
(d) 18
Ans: (c)
Sol:
let A = {1, 2, 3, 4}
R is defined on A × A such that since
R = {((a, b), (c, d)) : 2a + 3b = 3c + 4d}
since a , b , c , d ? A
Let possible values of 2a + 3b = L1 and possible values of 3c + 4d = L2
Common values of Common values of 2a + 3b = 3c + 4d
7, 10, 11, 13, 14, 15, 16, 17, 18, 20
value 7, 10, 13, 15, 16, 17, 18, 20
occurs 1 time in L1 and 1 time in L2
e.g value 7 occurs 1 time in L1 & 1 time in L2 total = 1 × 1 = 1
so, total number of these types of elements in R = 8 --- (1)
value 11 and 14 occurs 2 times in L1 and 1 time in L2
e.g value 11 occurs 2 time in L1 & 1 time in L2 total
elements in R is 2 × 1 = 2
so total number these type of elements = 2 + 2 = 4 --- (2)
total number of elements in R = 8+4 = 12
Q2: Consider two sets A = {x ? Z : | (| x - 3| - 3) | = 1} and
Then the number of onto functions f : A ? B is equal to :
(a) 32
(b) 81
(c) 79
(d) 62
Ans: (d)
Sol:
Page 5
JEE Main Previous Year Questions (2021-2026):
Sets, Relations and Functions
(January 2026)
Sets, Relations
Q1: Let R be a relation defined on the set {1, 2, 3, 4} × {1, 2, 3, 4} by
R = {((a, b), (c, d)) : 2 a + 3 b = 3 c + 4 d }.
Then the number of elements in R is
(a) 6
(b) 15
(c) 12
(d) 18
Ans: (c)
Sol:
let A = {1, 2, 3, 4}
R is defined on A × A such that since
R = {((a, b), (c, d)) : 2a + 3b = 3c + 4d}
since a , b , c , d ? A
Let possible values of 2a + 3b = L1 and possible values of 3c + 4d = L2
Common values of Common values of 2a + 3b = 3c + 4d
7, 10, 11, 13, 14, 15, 16, 17, 18, 20
value 7, 10, 13, 15, 16, 17, 18, 20
occurs 1 time in L1 and 1 time in L2
e.g value 7 occurs 1 time in L1 & 1 time in L2 total = 1 × 1 = 1
so, total number of these types of elements in R = 8 --- (1)
value 11 and 14 occurs 2 times in L1 and 1 time in L2
e.g value 11 occurs 2 time in L1 & 1 time in L2 total
elements in R is 2 × 1 = 2
so total number these type of elements = 2 + 2 = 4 --- (2)
total number of elements in R = 8+4 = 12
Q2: Consider two sets A = {x ? Z : | (| x - 3| - 3) | = 1} and
Then the number of onto functions f : A ? B is equal to :
(a) 32
(b) 81
(c) 79
(d) 62
Ans: (d)
Sol:
So set B = {3, 4}
Let n(A) & n(B) be number of elements in set A and B respectively
n(A) = 6, n(B) = 2
Number of onto function f : A ? B is
= Total function - Into function
Total function = (n(B))
n(A)
= 2 6
number of Into function can be find using inclusion-exclusion principle
Number of into function =
2
C
1
(1)
6
2
C
1
(1)
6
= only one image or range left from set B.
Number of onto function = 2
6
-
2
C
1
(1)
6
= 64 - 2 = 62
Q3: Let A = {0, 1, 2, … ,9}. Let R be a relation on A defined by (x, y) ? R if and only if | x -
y | is a multiple of 3.
Given below are two statements :
Statement I : n (R) = 36.
Statement II : R is an equivalence relation.
In the light of the above statements, choose the correct answer from the options given
below :
(a) Statement I is correct but Statement II is incorrect
(b) Both Statement I and Statement II are correct
Read More