1.

In the permutations of n things r, taken together, the number of permutations in which m particular things occur together is ""^(n-m)P_(r-m)xx""^(r)P_(m).

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Solution :False
Arrangement of n things, taken r at a time in which m things occur together, we considered these m things as 1 group.
NUMBER of OBJECT excluding those m objects = (r - m)
Now, first we have to arrange (r-m+1) objects.
Number of ARRANGEMENTS `=(r-m+1)"!"` and m objects which we consider as 1 group, can be ARRANGED in `m"!"` ways.
`therefore` Required number of arrangements `=(r-m+1)"!" xx m"!"`


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