A112­8Combinations.notebook
November 18, 2014
Algebra 1
Ch.12 Notes Page 66
P66 12­8 Combinations
Sep 2­8:31 AM
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A112­8Combinations.notebook
November 18, 2014
Suppose you are making a sandwich with three of these ingredients:
Turkey, Cheese, Tomato, and Lettuce.
Below are the permutations of the four ingredients listed 3 at a time.
How many different sandwiches could you really make?
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A112­8Combinations.notebook
November 18, 2014
Combinations
An Arrangement of Items where ORDER IS NOT IMPORTANT
How many ways can you pick 2 out of 3 letters when order is not important from the letters A, B, C ???
Jan 10­11:43 AM
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A112­8Combinations.notebook
November 18, 2014
Combination Calculation
n C r
n = how many things in the group.
r = how many of the things that you are picking at a time.
Start at the number n and use the first r numbers going toward zero.
Just like a Permuation.
However, you have to divide by r! to get rid of all of the duplicates.
How many ways can you pick 3 people out of 8 when Order is Not Important?
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A112­8Combinations.notebook
November 18, 2014
Example
Twenty people report for jury duty.
How many differnt twelve person juries can be chosen?
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A112­8Combinations.notebook
November 18, 2014
Special Combinations
5 C 5 = ?
4 C 4 = ?
Jan 12­10:09 AM
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A112­8Combinations.notebook
November 18, 2014
HW #72
1­6 P44 #1­4,6,10,14
12­7 P702 #1­5,7­14
12­8 P709 #1­5,11,12
Please put your name and class period at the top of the homework.
Also include the homework number.
Oct 14­2:27 PM
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