tough combination problem

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tough combination problem

by varun007 » Fri Aug 29, 2008 9:09 am
You have a six-sided cube and six cans of paint, each a different color. You may not mix colors of paint. How many distinct ways can you paint the cube using a different color for each side? (If you can reorient a cube to look like another cube, then the two cubes are not distinct.)

(A) 24
(B) 30
(C) 48
(D) 60
(E) 120

pls can somebody explain in detail

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by pranavc » Fri Aug 29, 2008 11:24 am
This is a tough one. I am interested in getting the explanation for this.

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Re: tough combination problem

by Ian Stewart » Fri Aug 29, 2008 12:24 pm
varun007 wrote:You have a six-sided cube and six cans of paint, each a different color. You may not mix colors of paint. How many distinct ways can you paint the cube using a different color for each side? (If you can reorient a cube to look like another cube, then the two cubes are not distinct.)

(A) 24
(B) 30
(C) 48
(D) 60
(E) 120

pls can somebody explain in detail
That is a tricky problem. Say we have six colours, Red, Green, Yellow, Purple, Black and White.

I must paint one side Red. I then have 5 choices for the colour which is opposite Red. Let's pretend that Purple is opposite Red for now, and we'll multiply by 5 at the end to get the total (and notice we're already down to B, D or E, because the answer must be divisible by 5).

Now, one of the four remaining faces must be Yellow. There are 3 choices for which colour should be opposite Yellow, then 2 choices for how to arrange the remaining two colours.

So there should be 5*3*2 = 30 choices in total.
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by vishubn » Fri Aug 29, 2008 12:42 pm
Hi Ian

I was eagerly waitng fr the solution and thanks for it :)
But could u please elaborate again ! if u dont mind concept still not clear ( my weak point is with these problem types )

Vishu