You have the right idea just multiply the numbers as they are all independent.

The first book in the stack is 1 of 9, the next is 1 of 8, the third is 1 of 7 etc. So the answer is

Assuming the same number is successive parts of the code are valid. then you have 3 independent choices of 60 so

This is like the book stack problem but you need just an arrangement of 3 from twelve. First is 1 of 12 second is 1 of 11 and third is 1 of 10. So

.

You can consider the men and women to be independent since there is an odd number and they must alternate the men have to sit on the ends.

So you have 5! arrangements of the men and 4! arrangements of the women which are independent and so the total answer is

You have to take each one over the course of the day. There are seven periods and seven subjects so this is just like the book stack problem.

Hope this helps.