Ans:1. I have 3 Maths books, 2 Science books and 4 English books which are all different. how many ways can I arrange the books on a shelf so that books of the same subject are put together?

2. How many different 5 digit numbers that are odd and less than 50 000 can be formed using the digits 2,3,4,5,6,7,8 without repetition?

3. Find the number of different 7-digit numbers (not beginning with zero) that can be formed using the digits 0-9 without repetition if the number is a multiple of 5.

1. 1728

2. 480

3. 329280

Any help please? I need to turn this is in by tomorrow. TIA.