61. The set of all permutations on a set X is denoted by:
A. SX
B. XS
C. Sx
D. XS
62. The set Sn is a group under the operation of … of permutations.
A. Addition
B. Subtraction
C. Multiplication
D. Composition
63. The order of symmetric group of degree n is:
A. n
B. n!
C. n!/2
D. ( n/2 )!
64. Composition of permutations is not:
A. Associative
B. Closed
C. Commutative
D. All of these
67. If two cycles act on mutually disjoint sets, then they:
A. can commute
B. must commute
C. don’t commute
D. None of these
68. If α = (1 2 3) and β = (5 7 8), then:
A. αβ = I
B. βα = I
C. αβ = βα
D. αβ 6= βα
69. Every permutation of degree n can be written as a … of cyclic permutations acting on mutually disjoint sets.
A. Sum
B. Difference
C. Product
D. Quotient
