Sect. 12-2 Permutations. Def: When a group of objects or people are arranged in a certain order, the...
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Transcript of Sect. 12-2 Permutations. Def: When a group of objects or people are arranged in a certain order, the...
Def: When a group of objects or people are arranged in a certain order, the arrangement is called a permutation.
1.Suppose a Theater owner has 11 films for an 8 screen theater. How many different arrangements are there for 8 screens to show 11 movies?
Def: The number of permutations of n objects taken r at a time is defined as
!!
,rn
nrnP
Where n! is factorial
2. Find 8!
3. (use formula) Suppose a Theater owner has 11 films for an 8 screen theater. How many different arrangements are there for 8 screens to show 11 movies?
5.How many ways can 2 math books, 4 geography books, 4 English books, 5 history and 3 physics books be arranged on a shelf?
Def: The number of permutations of n objects of which p are alike and q are alike is given by
!!
!
qp
n
7.There are 4 people seated at a round table. How many arrangements are possible?
Reflections such as keys on a ring : there are half as many