00:01
In the first question, we want to find the number of ways four girls and three boys can sit in a row such that just the girls are to sit next to each other.
00:13
That would mean the four girls are treated as being together as one block.
00:21
So the four girls and the boys can be arranged around them.
00:28
Now in general, if i have n distinct objects and i want to arrange n distinct objects in a row, it would be n factorial ways.
00:46
So in this case, for the four girls, there is four factorial ways to arrange the girl within the block here.
00:54
The block is to make them stay together.
00:56
Now the block is treated as one entity and each of the boys are treated as separate entities.
01:02
So we have one, two, three, four entities.
01:06
So there's another four factorial ways to arrange these four entities.
01:10
So the answer would be four factorial times four factorial...