31-#27

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Source: — Problem Solving |

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by keepsmilinyaar » Sun Aug 19, 2007 11:02 pm
Is the answer C?

l:w:h = 3:2:2 = k
l = k/3 ; w = k/2 ; h = k/2

lwh = x

(k^3)/12 = x

k =

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(12x)^ (1/3)
h = k/2 =

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 {(12x)^ (1/3) }/2
h =

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 {(12x/8)^ (1/3) }
h =

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 {(3x/2)^ (1/3) }

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by devesh » Mon Aug 20, 2007 12:46 am
B

method is same as above

only difference is
l:w:h = 3:2:2 implies
l = 3k ; w = 2k ; h = 2k

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by magical cook » Wed Aug 22, 2007 10:08 am
Sorry for the late response...

Yes - OA is B. :)

I understand that x = k^3 / 12 but how do you get B from the point?

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by keepsmilinyaar » Wed Aug 22, 2007 6:40 pm
hi,

well what devesh says is:

l:w:h = 3:2:2 implies
l = 3k ; w = 2k ; h = 2k

Therfore the equation now becomes
lwh = x
==> 3k * 2k * 2k = x
==> (12)k^3 = x

instead of x = k^3 / 12

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by tanyajoseph » Thu Aug 23, 2007 3:31 am
How does 12*K^3 become K^3/12????