Permutation and combinations
permutations deal with arrangement of objects and combinations with selection of objects
in an arrangement of course the order in which the objects are placed does matter,e.g. if students A,B,C,D are to be made to stand in a line then ABCD arrangement is different from the arrangement say BADC.
In combinations the order is not important , but how many objects are selected from how many objects is important.
e.g. if we have to select 5 students from a class of 25, the answer is C(25,5). Here the order in which they are chosen doesn't matter.
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