2006-06-12 00:50:22 · 11 answers · asked by goring 6 in Science & Mathematics ➔ Mathematics
I forgot to mention we must apreciate the Librarian too.You can see how many books they have to arrange.
2006-06-12 07:34:42 · update #1
Jimbo is the first person with the correct answer.
The first book you put on the shelf can be selected from the 6 books available and can be placed on the shelf either upright or upside down. There are 12 possibilities for the first book (6 books multipled by two ways round).
With one book on the shelf you now have 5 books remaining from which you select one and place it either upright or upside down on the shelf. But now there are only 10 possibilities (5 x 2).
With 4 books remaining there are 8 possibilities (4 x 2).
With 3 books remaining there are 6 possibilities (3 x 2).
With 2 books remaining there are 4 possibilities (2 x 2).
With 1 book remaining there are 2 possibilities (1 x 2).
To calculate the total number of possible ways to arrange the books you need to multiply together all the individual possibilities... 12 x 10 x 8 x 6 x 4 x 2... which equals 46,080.
2006-06-12 01:39:43 · answer #1 · answered by Trevor 7 · 0⤊ 1⤋
12 X 10 X 8 X 4 X 2 = 7680
You have 12 choices for the first book, any of the 6 books, either rightside up or upside down.
This will leave 5 books that you can pick from for the second book and seeing as any can be rightside up or upside down, there are 10 choices.
Continue with each book.
2006-06-12 08:00:34 · answer #2 · answered by fire4511 7 · 0⤊ 0⤋
i think it is 46080-6!
Nw for the first book thr will be 12 choices, either rightside up or upside down for any of the 6 books.
nw the remaining 5 books can be picked from for the second book and seeing as any can be upside up or upside down, there are 10 choices.
same cases with each of the book
so it b'comes : 12 * 10 * 8 * 6 * 4 * 2 = 46080
now for thr are possibilities that the books title can be facing u or opposite to u
nw thr will be 6! possibilities that the books titile to be facing opposite
so here is the no
46080-6!
2006-06-12 09:11:46 · answer #3 · answered by abhisek g 1 · 0⤊ 0⤋
12 X 10 X 8 X 4 X 2 = 7680
2006-06-12 08:28:54 · answer #4 · answered by Apoorva 3 · 0⤊ 0⤋
12*10*8*6*4*2 = 46,080
Normally right-side up it would 6! = 6x5x4x3x2x1 = 720
But since each book can also be upside down, there are 12 possibilities, instead of 6, for the first book; 10 instead of 5 for the 2nd, etc.
2006-06-12 08:02:37 · answer #5 · answered by Jimbo 5 · 0⤊ 0⤋
For the books to be arranged upright or upside down.. then we'll assume that we have 12 books ( upright books + uspide down books )
No. of ways = 12P6 = 12 !/6 ! = 665280 ways
2006-06-12 07:56:36 · answer #6 · answered by jmdanial 4 · 0⤊ 0⤋
720
2006-06-12 07:58:13 · answer #7 · answered by amin :-) 2 · 0⤊ 0⤋
6!=720
720*2=1440
but you can have some up and some down so you add 719 (because if you have all up and all down it would be the same as before)
1440+719=2159
2006-06-12 08:08:44 · answer #8 · answered by ♥ The One You Love To Hate♥ 7 · 0⤊ 0⤋
Can you place the books on their sides? otherwise it would be
24x20x16x12x8x4=2949120
2006-06-12 11:12:30 · answer #9 · answered by Bob 5 · 0⤊ 0⤋
its should be 1440
2006-06-12 08:01:49 · answer #10 · answered by Teddy 1 · 0⤊ 0⤋