-2 Combinations

• Combination-order doesn’t matter; can have repition or not

• Graphing calculator• n#,math,PRB 3,r#,enter

!

!( )!

n nnCr

r r n r

Example

• 5 cousins at a family reunion decide that 3 of them will go to pick up a pizza. How many ways can they choose the 3 people to go?5

103

Multiple events-Combination with fundamental counting principle

• 5 cards are drawn from a standard deck of cards. How many hands consist of 3 clubs and diamonds.

• 52 cards in a deck, 13 clubs, 13 diamonds

13 13286 78 286 78 22308

3 2

Combination with total• A wallet contains a $1 bill, a $5 bill, $10 bill,

$20 bill. How many different sums of money can be made from the money in the wallet?

41 1 4 6 4 15

4

44

3

46

2

44

1

Assignment