# Shared Flashcard Set

## Details

S5.5 - Counting Techniques
Counting Techniques
8
Mathematics
11/05/2013

Term
 Multiplication rule of counting
Definition
 If there are p selections for the first choice, q selections for the second choice, and r selections for the third choice, the task can be done in p x q x r
Term
 n! =
Definition
 n(n-1)3! = 1 x 2 x 3 = 6
Term
 Permutation of n distinct objects
Definition
 An ordered arrangement in which r objects are chosen from n distinct objects and repetition is not allowed14p3 = 14 x 13 x 12
Term
 nPr =
Definition
 n!/(n-r)! if
Term
 Combination
Definition
 A collection, without regard to order, of n distinct objects without repetition
Term
 nCr =
Definition
 nPr/r! = n!/r!(n-r)
Term
 Permutation with non-distinct items
Definition
 The number of permutations of n objects of which n1 are one kind, n2 are of a second kind,…, and nk are of a k-th kind
Term
 Permutation with non-distinct items =
Definition
 n!/n1!n2!…nk!
Supporting users have an ad free experience!