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9-5 Combinations (pgs 387-390). Indicator- D7. Combinations - an arrangement where order does not matter Example 1 How many different two topping pizzas can be made from 5 toppings? (Does it matter if you pick pepperoni then sausage or sausage then pepperoni?) 5 C 2
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9-5 Combinations(pgs 387-390) Indicator- D7
Combinations- an arrangement where order does not matter Example 1 How many different two topping pizzas can be made from 5 toppings? (Does it matter if you pick pepperoni then sausage or sausage then pepperoni?) 5C2 Find the permutation of the 5 toppings- 5X4 =20 ÷ by the ways to arrange two toppings 2X1= 2 There are 10 different two topping pizzas.
Example 2 Jen can invite three of the 12 girls in her class to a party. How many different arrangements can there be? (does it matter if you’re picked 1st or 3rd?) 12C3 = 12X11X10 = 1320 = 220 3! 6 There are 220 different combinations of girls that can be invited.
How many ways can a president, vice-president and secretary be chosen from the 10 students on student council? (Are the chances of being president the same as being secretary?) This is a …….. Permutation 10P3 =10X9X8 = 720 Ways There are 720 ways to choose officers.
Decide if each problem is a permutation or combination then solve. 8 players are playing each other in a checker tournament. How many games will be played? 8 C 2 How many ways to pick 6 starters from a 12 member volleyball team? 12 C 6 How many ways can you arrange the letters in the word “word?” 4 P4 W-O-R-D