9-5 Combinations Find the number of combinations of a set of objects
Ex) We want to choose a committee of 2 from 4 people. How many ways to do this? <ul><li>Demonstrate using volunteers. </li></ul>
Coach Smith wants to select co-captains for her basketball team. She will select two girls from the four oldest members on the team: Amber, Danielle, Leah, and Emma <ul><li>Use the first letter of each name to list all of the permutations of co-captains. How many are there? </li></ul><ul><li>Cross out any arrangement that contains the same letters as another one in the list. How many are there now? </li></ul><ul><li>Explain the difference between the two lists above. </li></ul>
Combination <ul><li>An arrangement, or listing, of objects in which order is not important. </li></ul><ul><li>For example, choosing Emma and Amber is the same as choosing Amber and Emma. </li></ul>
4 players taken 2 at a time. <ul><li>4*3 </li></ul><ul><li>2! </li></ul>
Select 3 toppings to go on pizza from 13 different toppings
Paul’s Pizza Parlor is offering a large two-topping pizza for $14.99. There are five toppings from which to choose. How many different two-topping pizzas are possible?
A checkers tournament features each of the top 8 regional players playing every opponent one time. The 2 players with the best records will then play in a final round to determine the champion. How many matches will be played if there are no ties?
With a partner Handout—right side only Combination Code
Journal <ul><li>In a t-table—describe two situations in which order of selection is important and when order is not important. </li></ul>