Nine toys are to be packed in 9 boxes if five of them are to big for three boxes then the number of ways in which they can be packed is

There are 5 big articles and 4 small articles. Similarly 6 big boxes and 3 small boxes.

Think that big articles can only be put in big boxes but small articles can be put in any type of box (big or small). Hence we will place big articles first, as their placement is conditional. Because selections with conditions must be dealt first.

First of all select 5 big boxes out 6 big boxes (6C5) in which 5 big articles can fit. Then arrange these 5 articles in these selected 5 boxes in (5!) ways.

Finally put remaining 4 small articles in remaining 4 boxes (which are remaining 1 big and 3 small boxes) (4!).

So Ans will be (6C5) * (5!) * (4!) = 17280


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