1. 12.3 Find Probability Using Combinations
Mrs. vazquez
Geometry

2. (S.cp.)1 & 9, (s.md)6 & 7 Essential Question:
How are many different arrangements can there be?
Objective:
Students will be able to use combinations to count possibilities.

3. combinations definition:
a selection of objects in which order is NOT important

4. combinations formulas
nCr =
the # of combinations of n objects taken r at a time, where r ≤n
Ex: 4C2 = =
= 6

5. solve
You order a sandwich at a restaurant. You can choose 3 sides from a list of 8. How many combinations of side dishes are possible?

6. solve
Mr. Wall has selected 20 photos, including one of you & one of a friend, to use in a collage for the yearbook. The photos are places at random. There is room for 2 photos at the top of the page. What is the probability that your photo & your friend’s are the two placed at the top of the page?