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Offline AHMAD209

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hello there i need help
« on: 08/06/2009 00:55:29 »
hello there i want expalanaitions for that questions plz...
1- 4 books are arranged on a book shelf . the positions of the books are numbered 1 throgh 4 ,from the left to right . for the following pair of conditions , how many possiblr orderings are there ? c sits to the right of b . b sits next to d only if b sits next c ?(4-6-8-10-12) answer:4<<<how is that


2- A cupboard has five shelves numbered 1 through 5 , from bottom on top ...each shelf has 2 compartements. there are 8 items A,B,C,D,E,F,G,H in the cupboard , no two of which are in the same compartement .items D and Eare on the same shelf . B is on the shelf directly below G . if a shelf contain only one item , it cannot be directly above or directly below another shelf that contains only one item . C is the only item on one of the shelves . there is only one item on the fourth shelf . which one of the following is a complete and accurate list of the items any one of which could be on the top shelf ?
( D- D,E,G,C - D,E,G,B - D,E,G,C,F -D,E,G,H,F,A ) ANS: D,E,G,H,F,A<<<<<how is that



 

Offline Hadrian

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Re: hello there i need help
« Reply #1 on: 08/06/2009 13:58:35 »
You would have 40,320 ways of arranging the books as long as they are all right side up with the spine out.

8 options for the 1st book, 7 for the 2nd, 6 for the 3rd, 5 for the 4th, 4 for the 5th, 3 for the 6th, 2 for the 7th and 1 for the 8th. Multiplying these numbers out:

8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 40,320.
 

Offline AHMAD209

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Re: hello there i need help
« Reply #2 on: 08/06/2009 18:51:39 »
how is that
 

Offline Don_1

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Re: hello there i need help
« Reply #3 on: 09/06/2009 08:22:56 »
Steady on now..... Hadrian has done your homework for you, now you want him to explain it.
 

Offline Hadrian

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hello there i need help
« Reply #4 on: 13/06/2009 18:56:16 »
Haven’t a clue………………………. LOL
 

Offline Make it Lady

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hello there i need help
« Reply #5 on: 13/06/2009 20:12:41 »
I never think too much about where I put my books and cupboard items so why do mathematicians? I heard one getting excited about football saying that it was geometry in action.
 

Offline Hadrian

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hello there i need help
« Reply #6 on: 16/06/2009 14:55:51 »
I never think too much about where I put my books and cupboard items so why do mathematicians? I heard one getting excited about football saying that it was geometry in action.

you got all the angles there Lady. i would have said curves but i don't know you that well LOL
 

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hello there i need help
« Reply #6 on: 16/06/2009 14:55:51 »

 

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