surface area of cubes

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surface area of cubes

by ritula » Fri Sep 19, 2008 2:30 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 s_kaks » Fri Sep 19, 2008 3:04 am
sufrace area of cube of 4cm = 4 *4*6 = 96

No of cubes of 1cm carved out of 4cm cubes = 64
surface area = 1* 1* 6* 64 = 384

therefore % increase = (384-96 / 96) * 100 = 300 %

OA pls?

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OA

by ritula » Fri Sep 19, 2008 4:07 am
OA is D indeed
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by Indradeep » Fri Sep 19, 2008 4:16 am
It is 300%(D)

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by vishubn » Thu Sep 25, 2008 5:09 am
sufrace area of cube of 4cm = 4 *4*6 = 96

No of cubes of 1cm carved out of 4cm cubes = 64
surface area = 1* 1* 6* 64 = 384
i missed out this part /??? how did u get this

mush appreciated

Vishu

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by stop@800 » Thu Sep 25, 2008 6:48 am
vishubn wrote:
sufrace area of cube of 4cm = 4 *4*6 = 96

No of cubes of 1cm carved out of 4cm cubes = 64
surface area = 1* 1* 6* 64 = 384
i missed out this part /??? how did u get this

mush appreciated

Vishu
surface area of cube = 6*a*a and
volume of cube = a*a*a

with volume you will find number of 1*1*1 cubes created from 4*4*4 cube.