# Set Operations

Set Operations 1

1. The union of the sets {1, 2, 5} and {1, 2, 6} is the set _______________
a) {1, 2, 6, 1}
b) {1, 2, 5, 6}
c) {1, 2, 1, 2}
d) {1, 5, 6, 3}

2. The intersection of the sets {1, 2, 5} and {1, 2, 6} is the set _____________
a) {1, 2}
b) {5, 6}
c) {2, 5}
d) {1, 6}

3. Two sets are called disjoint if there _____________ is the empty set.
a) Union
b) Difference
c) Intersection
d) Complement

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4. Which of the following two sets are disjoint?
a) {1, 3, 5} and {1, 3, 6}
b) {1, 2, 3} and {1, 2, 3}
c) {1, 3, 5} and {2, 3, 4}
d) {1, 3, 5} and {2, 4, 6}

5. The difference of {1, 2, 3} and {1, 2, 5} is the set ____________
a) {1}
b) {5}
c) {3}
d) {2}

6. The complement of the set A is _____________
a) A – B
b) U – A
c) A – U
d) B – A

7. The bit string for the set {2, 4, 6, 8, 10} (with universal set of natural numbers less than or equal to 10) is ____________________
a) 0101010101
b) 1010101010
c) 1010010101
d) 0010010101

8. Let Ai = {i, i+1, i+2, …..}. Then set {n, n+1, n+2, n+3, …..} is the _________ of the set Ai.
a) Union
b) Intersection
c) Set Difference
d) Disjoint

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9. The bit strings for the sets are 1111100000 and 1010101010. The union of these sets is ___________
a) 1010100000
b) 1010101101
c) 1111111100
d) 1111101010

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10. The set difference of the set A with null set is __________
a) A
b) null
c) U
d) B

Set Operations – 2

1. Let the set A is {1, 2, 3} and B is {2, 3, 4}. Then the number of elements in A U B is?
a) 4
b) 5
c) 6
d) 7
Explanation: AUB is {1, 2, 3, 4}.

2. Let the set A is {1, 2, 3} and B is { 2, 3, 4}. Then number of elements in A ∩ B is?
a) 1
b) 2
c) 3
d) 4

3. Let the set A is {1, 2, 3} and B is {2, 3, 4}. Then the set A – B is?
a) {1, -4}
b) {1, 2, 3}
c) {1}
d) {2, 3}
Explanation: In A – B the common elements get cancelled.

4. In which of the following sets A – B is equal to B – A?
a) A = {1, 2, 3}, B = {2, 3, 4}
b) A = {1, 2, 3}, B = {1, 2, 3, 4}
c) A = {1, 2, 3}, B = {2, 3, 1}
d) A = {1, 2, 3, 4, 5, 6}, B = {2, 3, 4, 5, 1}

5. Let A be set of all prime numbers, B be the set of all even prime numbers, C be the set of all odd prime numbers, then which of the following is true?
a) A ≡ B U C
b) B is a singleton set.
c) A ≡ C U {2}
d) All of the mentioned

6. If A has 4 elements B has 8 elements then the minimum and maximum number of elements in A U B are ____________
a) 4, 8
b) 8, 12
c) 4, 12
d) None of the mentioned

7. If A is {{Φ}, {Φ, {Φ}}}, then the power set of A has how many element?
a) 2
b) 4
c) 6
d) 8

8. Two sets A and B contains a and b elements respectively. If power set of A contains 16 more elements than that of B, value of ‘b’ and ‘a’ are _______
a) 4, 5
b) 6, 7
c) 2, 3
d) None of the mentioned

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9. Let A be {1, 2, 3, 4}, U be set of all natural numbers, then U-A’(complement of A) is given by set.
a) {1, 2, 3, 4, 5, 6, ….}
b) {5, 6, 7, 8, 9, ……}
c) {1, 2, 3, 4}
d) All of the mentioned

Explanation: U – A’ ≡ A.10. Which sets are not empty?
a) {x: x is a even prime greater than 3}
b) {x : x is a multiple of 2 and is odd}
c) {x: x is an even number and x+3 is even}
d) { x: x is a prime number less than 5 and is odd}