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PS Percentage problem

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Junior | Next Rank: 30 Posts
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by jcmsolis » Mon Apr 14, 2008 10:56 am
A 4 cm cube is cut into 1 cm cubes. What is the percentage increase in the surface area after such cutting?

* 4%
* 166%
* 266%
* 300%
* 400%
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by simplyjat » Mon Apr 14, 2008 12:20 pm
Surface area of the cube = 6*Side*Side

Initial surface area of one cube = 6 * 4 * 4 = 96
New surface are of 64 cubes = 64 * 6 * 1 * 1 = 384

%increase = (384 - 96)/96 = 320 / 96 = 333.33 %
Did you miss something in the question...
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by tmmyc » Mon Apr 14, 2008 12:51 pm
simplyjat wrote:Surface area of the cube = 6*Side*Side

Initial surface area of one cube = 6 * 4 * 4 = 96
New surface are of 64 cubes = 64 * 6 * 1 * 1 = 384

%increase = (384 - 96)/96 = 320 / 96 = 333.33 %
Did you miss something in the question...
simplyjat, you were exactly right, except (384 - 96)/96 = 288 / 96 = 300% increase.
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by dalwow » Tue Apr 15, 2008 7:37 am
Hey guys, why do we now use 64? I'm not sure where that came from. Thanks
Still Learning
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by simplyjat » Tue Apr 15, 2008 7:43 am
tmmyc wrote:
simplyjat wrote:Surface area of the cube = 6*Side*Side

Initial surface area of one cube = 6 * 4 * 4 = 96
New surface are of 64 cubes = 64 * 6 * 1 * 1 = 384

%increase = (384 - 96)/96 = 320 / 96 = 333.33 %
Did you miss something in the question...
simplyjat, you were exactly right, except (384 - 96)/96 = 288 / 96 = 300% increase.
Silly mistakes... :wink:
simplyjat
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by tmmyc » Tue Apr 15, 2008 9:43 am
dalwow wrote:Hey guys, why do we now use 64? I'm not sure where that came from. Thanks
64 is the number of 1x1x1 cubes that make up the 4x4x4 cube.
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by cjiang16 » Tue Apr 15, 2008 5:45 pm
I will choose D.
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