Nine toys are to be packed in 9 boxes. If 5 of them are too big for 3 boxes, then the number of ways in which they can be packed is

There are 6 big, 3 small boxes. and 5 big articles and 4 small articles. 5 big articles can be packed in 6 big boxes. in 6p_5  ways. 4 small articles can be packed in remaining 4 boxes in 4! way. 

⇒No. of permutations =6p₅ (4!)