Permutation/Combination Flashcards
1
Q
How can you tell if something is a combination and what is the key word
A
A group where order does not matter (example is playing cards bc the order does not matter and you can arrange them in your hand)
Key word: group
2
Q
How can you tell if something is a permutation and what are the key words
A
Order does matter (example= 1st place winner receives $100, 2nd place winner receives $75, 3rd place winner receives $50)
Key words: orderings/arrangements
3
Q
What is the formula for permutations
A
P n,r = n! / (n-r)!
4
Q
What is the formula for combinations
A
C n,r= n! / r!(n-r)!
5
Q
How can you tell which value goes in for n and which value goes in for r?
A
N will always be greater than or equal to r
