This set of Discrete Mathematics Questions and Answers for Aptitude test focuses on “Cardinality of Sets”.

1. The cardianlity of the set A = {1, 2, 3, 4, 6} is:

a) 5

b) 6

c) Integer

d) None of the mentioned

View Answer

Explanation: 5, it is number of elements in the sets.

2. For two equal sets there:

a) Cardinality is same

b) Cardinality is different

c) May be same or different

d) None of the mentioned

View Answer

Explanation: Two equal sets should have same number of elements.

3. If A is a subset of B:

a) Cardinality of A is greater than B

b) Cardinality of B is greater than A

c) Can’t say

d) None of the mentioned

View Answer

Explanation: B contains all the elements of A, as well as other elements.

4. If there is bijection between two sets A and B then :

a) Cardinality of A is greater than B

b) Cardinality of B is greater than A

c) Cardinality of B is equal to A

d) None of the mentioned

View Answer

Explanation: If there is bijection then two sets A and B will be equinumerous and thus will have same cardinality.

5. Let a set E ={0,2,4,6,8….} of non-negative even numbers and O = {1, 3, 5, 7, 9,…..} of non-negative odd numbers then :

a) Cardinality of set E is greater thanthat of O

b) Cardinality of set O is greater than that of E

c) Cardinality of set E is equal to that of O

d) None of the mentioned

View Answer

Explanation: There is bijection then two sets E and O and they will be equinumerous and thus will have same cardinality.

6. State whether the given statement is true or false

Cardinality of the set of lower letter english alphabets is 26.

a) True

b) False

View Answer

Explanation: From a, b, c…z there will be 26 elements.

7. Cardinality of the set of even prime number under 10 is 4.

a) True

b) False

View Answer

Explanation: Since 2 is only even prime thus cardinality should be 1.

8. If for sets A and B there exists a injective function but not bijective function from A to B then:

a) Cardinality of A is stricly greater than B

b) Cardinality of B is strictly greater than A

c) Cardinality of B is equal to A

d) None of the mentioned

View Answer

Explanation: If there doesnot exist a bijective function from A to B that means there are some elements in B whose preimage is not in A, thus cardinality of B is strictly greater than A.

9. If cardinality of (A U B) = cardinality of A+ cardinality of B. This means:

a) A is a subset of B

b) B is a subset of A

c) A and B are disjoint

d) None of the mentioned

View Answer

Explanation: Thus if cardinality of (A U B) = cardinality of A+ cardinality of B ,it means they don’t have any element in common, n(A∩B) = 0.

10. If A is a subset of B and B is a subset of C,then cardinaity of A U B U C is equal to :

a) Cardinality of C

b) Cardinality of B

c) Cardinality of A

d) None of the mentioned

View Answer

Explanation: A U B U C = C, since a, b are subsets to C.

**Sanfoundry Global Education & Learning Series – Discrete Mathematics.**

To practice all areas of Discrete Mathematics for Aptitude test, __here is complete set of 1000+ Multiple Choice Questions and Answers__.