



 
The difference is that permutations take order into account whereas combinations do not. For example, if you are looking to choose 3 people from 5 then the number of choices (combinations) is _{5}C_{3} = 10 whereas if you want to form a lineup of three people from 5 then order is important and you can do this in 5x4x3 = 60 ways. In general _{n}P_{k} = k!_{n}C_{k} where _{n}P_{k} is the number of permutations of k objects from a set of n distinct objects and _{n}C_{k} is the number of combinations of k objects from a set of n distinct objects (and k!, k factorial,is k×(k1)...×3×2×1). Penny  


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