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Math 120 SP08
Section 6.4 Notes: Permutations & Combinations
Brodnick
Example
:
1. At the state track meet, 8 runners make it to their event final.
If ribbons will be awarded for each place, how
many ways can this be done?
*
An ordered arrangement of items is called a permutation of those items.
*
# of possible permutations of
n
items is
n
!
*
in your calculator: #
n
MATH
PRB
4:!
Examples
:
2. How many different ways can 7 people be seated in a row of chairs?
3. At the Olympics, only the top 3 finishers receive medals.
If there are 7 finalists, how many ways can the
medals be awarded?
*
A permutation of
n
items taken
r
at a time is an ordered list of
r
of the items chosen from a set of
n
items
*
Denoted
n
P
r
*
in your calculator: #
n
MATH
PRB
2: nPr
#
r
Example
:
4. 5 people apply for a $500 scholarship.
If the scholarship committee selects 2 people, how many ways can
the scholarship be awarded?
*
An unordered set of n items chosen r at a time is called a combination of those items.
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 Spring '08
 Brodnick
 Math, Permutations

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