Let A = {1, 2, 3, ..., 100} and R be a relation on A such that R = {(a, b) : a = 2b + 1}. Let be a sequence of k elements of R such that the second entry of an ordered pair is equal to the first entry of the next ordered pair. Then the largest integer k, for which such a sequence exists, is equal to : [2025]
8
5
6
7
(2)
Let the smallest value is in A = {1, 2, 3, ..., 100}.
Since,
The sequence is {(63, 31), (31, 15), (15, 7), (7, 3), (3, 1)}
k = 5
Let A = {–3, –2, –1, 0, 1, 2, 3}. Let R be a relation on A defined by if and only if . Let be the number of elements in R and m be the minimum number of elements required to be added in R to make it reflexive relation. Then + m is equal to [2025]
18
20
17
19
(1)
A = {–3, –2, –1, 0, 1, 2, 3}
xRy if and only if
y = –3
y = –2
y = –1
y = 0
y = 1
y = 2
y = 3
R = {(–3, –3), (3, –3), (–2, –2),(2, –2), (–2, –1), (2, –1), (–2, 0), (–1, 0), (0,0), (1, 0), (2, 0), (–1, 1), (0, 1), (1, 1), (0, 2)}
= 15
To make it reflexive we will add (–1, –1), (2, 2), (3, 3) in R
+ m = 15 + 3 = 18.
Let A = {–2, –1, 0, 1, 2, 3}. Let R be a relation on A defined by xRy if and only if y = max{x, 1}. Let be the number of elements in R. Let m and n be the minimum number of elements required to be added in R to make it reflexive and symmetric relations, respectively. Then + m + n is equal to [2025]
13
12
14
11
(2)
We have, A = {–2, –1, 0, 1, 2, 3} and
R = {(–2, 1), (—1, 1), (0, 1), (1, 1), (2, 2), (3, 3)}.
Now, number of elements in R i.e., = 6
For R to be reflexive,
R = {(–2, –2), (–1, –1), (0, 0), (–2, 1), (–1, 1), (0, 1), (1, 1), (2, 2), (3, 3)}
So, we need to add three elements to make it reflexive.
m = 3
For R to be symmetric,
R = {(–2, 1), (1, –2), (–1, 1), (1, –1), (0, 1), (1, 0), (1, 1), (2, 2), (3, 3)}
So, we need to add three elements to make it symmetric.
n = 3
So, + m + n = 6 + 3 + 3 = 12.
Let A = {–3, –2, –1, 0, 1, 2, 3} and R be a relation on A defined by xRy if and only if 2x – y {0, 1}. Let be the number of elements in R. Let m and n be the minimum number of elements required to be added in R to make it reflexive and symmetric relations, respectively. Then + m + n is equal to : [2025]
17
16
18
15
(1)
We have, A = {–3, –2, –1, 0, 1, 2, 3}, R is defined on A as xRy such that 2x – y {0, 1}.
i.e., 2x – y = 0 or 2x – y = 1
R = {(0, 0), (–1, –2), (1, 2), (0, –1), (2,3), (1, 1), (–1, –3)} i.e., = 7
For R to be reflexive, i.e., we need 5 more elements {(2, 2), (–1, –1), (3, 3), (–3, –3), (–2, –2)} so m = 5 and for R to be symmetric, we need 5 more elements {(–2, –1), (2, 1), (–1, 0), (3, 2), (–3, –1)}, so n = 5.
+ m + n = 7 + 5 + 5 = 17.
Let A = {0, 1, 2, 3, 4, 5}. Let R be a relation on A defined by (x, y) R if and only if max {x, y} {3, 4}. Then among the statements
() : The number of elements in R is 18, and
() : The relation R is symmetric but neither reflexive nor transitive. [2025]
both are true
only () is true
both are false
only () is true
(2)
R = {(0, 3), (3, 0), (0, 4), (4, 0), (1, 3), (3, 1), (2, 3), (3, 2), (3, 3), (1, 4), (4, 1), (2, 4), (4, 2), (3, 4), (4, 3), (4, 4)}
Number of elements in R = 16
is false.
Now, (0, 0), (1, 1), (2, 2), (5, 5) R R is not reflexive.
Again, let (a, b) R then (b, a) R
As max {a, b} = max {b, a} R is symmetric.
Now, R is not transitive as (0, 3), (3, 1) R but (0, 1) R.
is true.
The number of non-empty equivalence relations on the set {1, 2, 3} is: [2025]
5
6
7
4
(1)
Partitions of set {1, 2, 3} is {{1}}, {2}, {3}}, {{1, 2}, {3}}, {{1, 3}, {2}}, {{2, 3}, {1}}, {{1, 2, 3}}
Number of non-empty equivalence relations on the set {1, 2, 3} = 5.
Let R = {(1, 2), (2, 3), (3, 3)} be a relation defined on the set {1, 2, 3, 4}. Then the minimum number of elements, needed to be added in R so that R becomes an equivalence relation, is: [2025]
7
10
9
8
(1)
Let A = {1, 2, 3, 4}
R = {(1, 2), (2, 3), (3, 3)} [Given]
For an equivalence relation 'R' should be reflexive, symmetric and transitive.
Minimum elements that should be added are
(2, 1), (3, 2), (1, 1), (2, 2), (4, 4), (1, 3), (3, 1)
Minimum number of elements required = 7.
Let and
If , then is: [2025]
18
12
24
15
(2)
We have, and

From given figure, we get C = {(3, 0), (–3, 0), (0, 3), (0, –3)}
Let X = R R. Define a relation R on X as:
.
Statement I: R is an equivalence relation.
Statement II: For some (a, b) X, the set
S = {(x, y) X :(x, y) R (a, b)} represents a line parallel to y = x.
In the light of the above statements, choose the correct answer from the options given below: [2025]
Statement I is true but Statement II is false.
Statement I is false but State II is true.
Both Statement I and Statement II are false.
Both Statement I and Statement II is true.
(1)
Statement I:
Reflexive :
R is reflexive.
Symmetric :
R is symmetric.
Transitive :
and
Hence, relation R is equivalence relation.
Statement I is true.
For Statement II: (x, y) R (a, b), for some
So, Statement II is false.
The relation R = {(x, y) : x, y Z and x + y is even} is: [2025]
reflexive and transitive but not symmetric.
reflexive and symmetric but not transitive.
symmetric and transitive but not reflexive.
an equivalence relation.
(4)
R = {(x, y) : x, y Z and x + y is even}
For reflexive : x + x = 2x is even
For symmetric : x + y = y + x is even
For transitive : x + y is even and y + z is even then z + x is also even.
So, the relation is an equivalence.
Define a relation R on the interval by xRy if and only if . Then R is : [2025]
an equivalence relation.
reflexive but neither symmetric not transitive.
both reflexive and symmetric but not transitive.
both reflexive and transitive but not symmetric.
(1)
R is reflexive
Consider,
R is symmetric.
Now, if and
Adding both equation,
[]
R is transitive
Thus R is an equivalence relation.
Let . Define a relation R from S to R by:
Then, the sum of all the elements in the range of R is equal to: [2025]
(2)
We have,
Also,
Required sum =
.
The number of relation on the set A = {1, 2, 3}, containing at most 6 elements including (1, 2), which are reflexive and transitive but not symmetric, is __________. [2025]
(5)
Given, A = {1, 2, 3}
Let the relation be R on A, which is reflexive and transitive but not symmetric, then
(1, 1), (2, 2), (3, 3), (1, 2) R
Remaining elements are
(2, 1), (2, 3), (1, 3), (3, 1), (3, 2)
Case I : If relation contains exactly 4 elements 1 way
Case II : If relation contains exactly 5 elements, so we can add (1, 3) or (3, 2) 2 ways
Case III : If relation contains exactly 6 elements, so we can add (2, 3), (1, 3) or (1, 3), (3, 2) or (3, 1), (3, 2) 3 ways
Total number of relations is 6.
Let A = {1, 2, 3}. The number of relations on A, containing (1, 2) and (2, 3), which are reflexive and transitive but not symmetric, is __________. [2025]
(3)
For transitive : (1, 2) and (2, 3) R (1, 3) R
For reflexive : (1, 1), (2, 2), (3, 3) R
Now, for (2, 1), (3, 2), (3, 1); (3, 1) cannot be taken for not symmetric relation.
Case I : (2, 1) taken and (3, 2) not taken
Case II : (3, 2) taken and (2, 1) not taken
Case III : (2, 1) and (3, 2) are not taken
Therefore, 3 relations are possible.
Let . Let R be a relation on A 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: [2026]
33
32
35
34
(1)
R = {(-2, a), (-1, b), (0, c), (1, d), (2, e)}
a = {-2, -1, 0, 1, 2, 3, 4};
b = {-2, -1, 0, 1, 2, 3, 4}
c = {-2, -1, 0, 1, 2};
d = {-2, -1, 0};
e = {-2}
∴ No. of elements in R
= 7 + 7 + 5 + 3 + 1 = 23 =
Minimum number of element to be added to make it reflexive = m = 4
⇒ {(1, 1), (2, 2), (3, 3), (4, 4)}
Minimum number of element to be added to make it symmetric = n = 6
⇒ R = {(3, -2), (4, -2), (2, -1), (2, 0), (3, -1), (4, -1)}
+ m + n = 23 + 4 + 6 = 33
Let be a relation defined on the set by
Then the number of elements in is [2026]
15
6
18
12
(4)
(a, b) (c, d)
(1, 1) x
(1, 2) x
(1, 3) (1, 2)
(1, 4) (2, 2)
(2, 1) (1, 1)
(2, 2) (2, 1)
(2, 3) (3, 1)
(2, 4) (4, 1)
(3, 1) x
(3, 2) x
(3, 3) (1, 3)
(3, 4) (2, 3)
(4, 1) (1, 2)
(4, 2) (2, 2)
(4, 3) (3, 2)
(4, 4) (4, 2)
Let the relation R on the set be given by
Then the minimum number of elements required to be added in R, in order to make the relation symmetric, is equal to [2026]
1
2
4
3
(2)
R = {(3, 3), (7, 8), (11, 13)}
to make it symmetric (8, 7), (13, 11) must be added.
Let Let R be a relation on A defined by if and only if is a multiple of 3.
Given below are two statements:
Statement I: .
Statement II: R is an equivalence relation.
In the light of the above statements, choose the correct answer from the options given below. [2026]
Statement I is correct but Statement II is incorrect
Statement I is incorrect but Statement II is correct
Both Statement I and Statement II are incorrect
Both Statement I and Statement II are correct
(2)
Let A = {2,3,5,7,9} Let R be the relation on A defined by xRy if and only if . Let be the number of elements in R, and m be the minimum number of elements required to be added in R to make it a symmetric relation. Then is equal to : [2026]
25
23
27
21
(1)
To make it symmetric the elements to be added are
The number of elements in the relation is [2026]
86
89
67
77
(4)