math, accounting, programing

Discrete Mathematics Practice Quiz


1. What is a set?
A) A collection of duplicate elements
B) A collection of unique elements
C) A collection of ordered elements
Answer: B) A collection of unique elements


2. Which of the following is a subset of {1, 2, 3}?
A) {1, 2, 4}
B) {1, 2}
C) {1, 2, 3, 4}
Answer: B) {1, 2}


3. What is the power set of {a, b}?
A) {{}, {a}, {b}, {a, b}}
B) {{a}, {b}}
C) {{}, {a}}
Answer: A) {{}, {a}, {b}, {a, b}}


4. A relation R is reflexive if:

A) (a, b) ∈ R => (b, a) ∈ R

B) (a, b) ∈ R => (b, c) ∈ R

, C) (a, a) ∈ R for all a

Answer: C) (a, a) ∈ R for all a


5. A function f: A -> B is injective if:
A) f(a) = f(b) => a = b
B) f(a) = f(b) => a ≠ b
C) f(a) ≠ f(b) => a = b
Answer: A) f(a) = f(b) => a = b


6. What is the number of edges in a complete graph with n vertices?
A) n(n-1)/2
B) n(n+1)/2
C) n^2
Ans: A) n(n-1)/2


7. A graph is bipartite if:
A) It has no cycles
B) It has no odd cycles
C) It has no even cycles
Answer: B) It has no odd cycles


8. What is the formula for combinations?
A) n! / (r! * (n-r)!)