00:01
In the given question, we are provided with three novels, six poetry and four reference books.
00:10
Now we have to arrange these in such a way that the one category has all the books at the same place.
00:22
Now we will first check in how many ways we can arrange these categories.
00:27
So the three categories are 9, n, p and r.
00:32
So if we talk about the arrangement, so the arrangement can be written as npr, it means first we have novels, then we have poetries and then we have reference book.
00:43
Second will be, first we have novels, then we have reference book and then we have poetry.
00:48
Similarly, the other arrangements can be written as p -r -n, p -n -r -p -n -r -p -n and r -p -n and r -p.
00:59
So these are six in total.
01:03
But it is difficult to calculate the number of arrangement when the categories are very big in number...