Permutation and Combination (high school level)

Question

In how many ways can 4 Physics books and 3 Mathematics books be arranged on a shelf if a selection is made from 6 different Physics books and 5 different Mathematics books? In how many of these arrangements are the Physics books together.

The answer are 756,000 and 86,400

I don't know how to get these answers – DRV5 Jul 07 '16 at 00:50 — DRV5, Jul 07 '16 at 00:50

score 1 · Answer 1 · answered Jul 07 '16 at 00:53

I do not want to solve it for you, but here are some serious hints:

You select 4 out 6 and 3 out of 5 (order does not matter of course) and then you line them up. Assuming all books are different, you have 7! ways of doing this (for each selection of books, of course).

For the second problem, you still have the number of selections the same, but now you need to account for a different lining up: FFFFMMM, MFFFFMM and so on. And keep in mind all books are different.

Can you handle from here?

thanks, I think I can handle it now – DRV5 Jul 07 '16 at 00:56 — DRV5, Jul 07 '16 at 00:56

Permutation and Combination (high school level)

1 Answers1