Lagrange Theorem and Counting Principles - Question Bank

1. What is the primary implication of Lagrange's Theorem for the structure of finite groups?
A) It guarantees the existence of a unique subgroup for every divisor of the group's order.
B) It establishes that the order of every element and subgroup must divide the order of the group.
C) It proves that all finite groups are cyclic.
D) It provides a method for constructing all possible finite groups.
2. If there are 7 choices for the first letter of a word and 5 choices for the second letter, how many 2-letter words can be formed if repetition is allowed?
A) 7 + 5
B) 7 - 5
C) 7 * 5
D) 7^5
3. How many non-isomorphic groups of order 4 exist?
A) 1
B) 2
C) 3
D) 4
4. If a subgroup H has index 2 in G, what can be said about H?
A) H is always trivial.
B) H is always cyclic.
C) H is always a normal subgroup of G.
D) H is always abelian.
5. Consider the group of symmetries of an equilateral triangle (D_3). What is its order?
A) 3
B) 4
C) 6
D) 12
6. What does Cauchy's Theorem state for finite groups?
A) If G is a finite group and p is a prime dividing |G|, then G has an element of order p.
B) If G is a finite group and p is a prime dividing |G|, then G has a subgroup of order p.
C) If G is a finite group and p is a prime dividing |G|, then G is cyclic.
D) If G is a finite group and p is a prime dividing |G|, then G has a normal subgroup of order p.
7. If a group G has order 30, what are the possible orders of its subgroups?
A) Any divisor of 30
B) Only prime divisors of 30
C) Only divisors that are powers of primes
D) Only 1, 2, 3, 5, 6, 10, 15, 30
8. A password must be 4 characters long and can consist of uppercase letters or digits. How many possible passwords are there?
A) 26 * 10
B) (26+10)^4
C) 26^4 * 10^4
D) 4^26 * 4^10
9. Which counting principle is used when calculating the number of possible outcomes when rolling two distinct dice?
A) Addition Principle
B) Multiplication Principle
C) Inclusion-Exclusion Principle
D) Pigeonhole Principle
10. What is the total number of ways to arrange the letters in the word 'MISSISSIPPI'?
A) 11!
B) 11! / (4! * 4! * 2!)
C) 11! / (4! * 4! * 2! * 1!)
D) 11! / (4! * 4!)
11. If you have 5 different flavors of ice cream and you want to choose 2 different flavors for a cone, how many combinations are possible?
A) P(5,2)
B) C(5,2)
C) 5+2
D) 5*2
12. How many binary strings of length 8 are there?
A) 8
B) 16
C) 2^8
D) 8^2
13. In how many ways can a president, vice-president, and treasurer be selected from a club of 10 members?
A) C(10,3)
B) P(10,3)
C) 10^3
D) 10+3
14. What is the number of permutations of n distinct objects taken k at a time?
A) C(n,k)
B) P(n,k)
C) n^k
D) k^n
15. If H is a subgroup of G, and |G| = 24 and |H| = 6, what is the index [G:H]?
A) 2
B) 3
C) 4
D) 18
16. Consider the group of units modulo 5, U(5) = {1, 2, 3, 4} under multiplication modulo 5. What is the order of the subgroup generated by 2?
A) 1
B) 2
C) 3
D) 4
17. What is the order of the group of integers modulo n under addition, Z_n?
A) 1
B) n
C) n-1
D) infinity
18. If G is a group of order 12, which of the following is a possible order for an element in G?
A) 7
B) 8
C) 10
D) 4
19. Lagrange's Theorem is a fundamental result in which area of mathematics?
A) Number Theory
B) Abstract Algebra
C) Linear Algebra
D) Real Analysis
20. If G is a group and H is a subgroup, and g is an element of G, what is a left coset of H in G?
A) {hg | h in H}
B) {gh | h in H}
C) {g * h | h in H}
D) {h * g | h in H}
21. Which of the following is NOT necessarily true for any finite group G?
A) G has a subgroup of order 1.
B) G has a subgroup of order |G|.
C) G has an element of order |G|.
D) The order of every element of G divides |G|.
22. Consider the group Z_6 under addition modulo 6. What is the order of the element 4?
A) 1
B) 2
C) 3
D) 6
23. How many ways can you arrange 5 distinct books on a shelf?
A) 5
B) 10
C) 25
D) 120
24. If a set has n elements, how many subsets does it have?
A) n
B) 2n
C) 2^n
D) n^2
25. How many distinct permutations are there of the letters in the word 'APPLE'?
A) 5!
B) 5! / 2!
C) 5! / 3!
D) 5! / 2!3!
26. In how many ways can the letters of the word 'MATH' be arranged?
A) 4
B) 8
C) 12
D) 24
27. What is the formula for permutations, 'n permute k' (P(n,k))?
A) n! / (k! * (n-k)!)
B) n! / k!
C) n! / (n-k)!
D) (n-k)! / n!
28. What is the formula for combinations, 'n choose k' (C(n,k))?
A) n! / (k! * (n-k)!)
B) n! / k!
C) n! / (n-k)!
D) (n-k)! / n!
29. A committee of 3 people is to be selected from a group of 5 people. How many different committees can be formed?
A) 5 * 4 * 3
B) 5 + 4 + 3
C) 5 choose 3 (C(5,3))
D) 5!
30. If there are 3 routes from city A to city B, and 4 routes from city B to city C, how many distinct ways are there to travel from city A to city C via city B?
A) 3 + 4 = 7
B) 4 - 3 = 1
C) 3 * 4 = 12
D) 4 / 3
31. What does the addition principle (or addition rule) state?
A) If a task can be done in 'm' ways and another task can be done in 'n' ways, and the tasks cannot be done at the same time, then there are m*n ways to do either task.
B) If a task can be done in 'm' ways and another task can be done in 'n' ways, and the tasks cannot be done at the same time, then there are m+n ways to do either task.
C) If a task can be done in 'm' ways and another task can be done in 'n' ways, and the tasks can be done at the same time, then there are m+n ways to do either task.
D) If a task can be done in 'm' ways and another task can be done in 'n' ways, and the tasks can be done at the same time, then there are m*n ways to do either task.
32. Consider forming a 3-digit number using digits 1, 2, 3, 4, 5 without repetition. How many such numbers can be formed?
A) 5 * 5 * 5
B) 5 * 4 * 3
C) 5 + 4 + 3
D) 5!
33. If there are 'm' ways to do one thing and 'n' ways to do another, and these choices are independent, how many ways are there to do both?
A) m + n
B) m - n
C) m * n
D) m / n
34. What is the fundamental counting principle (also known as the multiplication principle)?
A) If an event can occur in 'm' ways and another independent event can occur in 'n' ways, then the two events can occur in sequence in m+n ways.
B) If an event can occur in 'm' ways and another independent event can occur in 'n' ways, then the two events can occur in sequence in m*n ways.
C) If an event can occur in 'm' ways and another independent event can occur in 'n' ways, then the two events can occur in sequence in m-n ways.
D) If an event can occur in 'm' ways and another independent event can occur in 'n' ways, then the two events can occur in sequence in m/n ways.
35. If G is a group of prime order p, then G is isomorphic to which group?
A) The cyclic group Z_p
B) The cyclic group Z_p^2
C) The symmetric group S_p
D) The alternating group A_p
36. What is the order of the alternating group A_4?
A) 12
B) 24
C) 6
D) 8
37. The set of all permutations of n distinct objects forms which algebraic structure?
A) A cyclic group
B) A non-abelian group
C) An abelian group
D) A ring
38. What is the order of the element (1 2 3) in the symmetric group S_3?
A) 1
B) 2
C) 3
D) 6
39. Which of the following is a subgroup of S_3?
A) A cyclic group of order 4
B) A cyclic group of order 3
C) A cyclic group of order 5
D) A cyclic group of order 6
40. Consider the symmetric group S_3. What is its order?
A) 3
B) 4
C) 6
D) 12
41. Which theorem is a generalization of Lagrange's Theorem for infinite groups?
A) Cauchy's Theorem
B) Sylow's First Theorem
C) The Fundamental Theorem of Finite Abelian Groups
D) The Jordan-Hölder Theorem
42. What is the converse of Lagrange's Theorem?
A) If a number 'n' divides the order of a group G, then G has a subgroup of order 'n'.
B) If a number 'n' divides the order of a group G, then G has an element of order 'n'.
C) If a group G has an element of order 'n', then 'n' divides the order of G.
D) If a group G has a subgroup of order 'n', then 'n' divides the order of G.
43. What is a necessary condition for a subgroup H to be a normal subgroup of G, related to cosets?
A) Every left coset is equal to the corresponding right coset.
B) The order of H must be equal to the order of G.
C) The index [G:H] must be 1.
D) H must contain only the identity element.
44. If a group G has order 10, which of the following cannot be the order of a subgroup of G?
A) 1
B) 2
C) 5
D) 7
45. Lagrange's Theorem also implies a relationship between the order of a group, the order of a subgroup, and the index of the subgroup. What is this relationship?
A) |G| = |H| * [G:H]
B) |H| = |G| * [G:H]
C) [G:H] = |G| * |H|
D) |G| + |H| = [G:H]
46. What is the index of a subgroup H in a group G, denoted by [G:H]?
A) The order of H
B) The order of G
C) The number of distinct left (or right) cosets of H in G
D) The number of elements in the intersection of H with its conjugates
47. In the context of Lagrange's Theorem, what is the relationship between the order of an element 'a' in a group G and the order of the group G?
A) The order of 'a' is equal to the order of G.
B) The order of G divides the order of 'a'.
C) The order of 'a' divides the order of G.
D) The order of 'a' is always a prime number.
48. Consider the group of integers modulo 12 under addition, Z_12. What is the order of the subgroup generated by 3, which is {0, 3, 6, 9}?
A) 3
B) 4
C) 6
D) 12
49. If G is a finite group and H is a subgroup of G, then Lagrange's Theorem states that:
A) |H| = |G|
B) |G| divides |H|
C) |H| divides |G|
D) |H| is a prime number
50. What is the statement of Lagrange's Theorem regarding the order of a subgroup?
A) The order of an element in a group divides the order of the group.
B) The order of a subgroup divides the order of the group.
C) The order of a group is always prime.
D) The order of the product of two elements is the product of their orders.