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# There are 64 big cube-shaped bricks painted with yellow. How many smal

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There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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Updated on: 07 Oct 2018, 05:38
00:00

Difficulty:

55% (hard)

Question Stats:

46% (01:47) correct 54% (01:43) wrong based on 73 sessions

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There are 64 big cube-shaped bricks painted with yellow. How many small bricks are required to cover the entire outer surface of the big cube so that the yellow paint does not show at all?

A. 32
B. 64
C. 96
D. 180
E. 216

Weekly Quant Quiz #3 Question No 3

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Originally posted by gmatbusters on 06 Oct 2018, 10:09.
Last edited by gmatbusters on 07 Oct 2018, 05:38, edited 2 times in total.
Renamed the topic, edited the question and added the OA.
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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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11 Oct 2018, 02:02
1
Shouldn't the correct answer be 80 because the face that the cube rests on is not visible? So, 16x5=80.
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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 10:09

Official Solution

In order to make it so that the yellow paint does not show, 6 white cubes on the right can be put on the surface of each cube. 16 cube-shaped bricks are needed for the white cube on the left and from 16*6=96, there should be at least 96 cube-shaped bricks in order for to cover all the yellow paint. C is the answer.

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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 10:14
Each cube has 6 faces.

We need to cover one face.

Assume 64 cubes make up one big cube.

We need 4x4 cubes per face.

Hence 16x6 such cubic bricks are necessary = 96
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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 10:18

Best,
G
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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 10:26
assuming we are looking for min numbers........ !!!

When stakked together in cubic for we have 16 bricks in each 6 faces... total req= 16*6 = 96......Ans C
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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 10:36
Is the question worded correctly?

We have a big cube of dimensions 4*4*4

In order to cover this cube from all directions, the existing cube has 16 smaller faces on each face of the big cube. So in order to cover the yellow painted cubes, we need 16 new cubes on each face

New cubes added = 16*6 = 96

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Re: There are 64 big cube-shaped bricks painted with yellow. How many smal  [#permalink]

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06 Oct 2018, 11:07
There are 64 big cube-shaped bricks painted with yellow. How many small bricks are required to cover the entire outer surface of the big cube so that the yellow paint does not show at all?

64 cube shaped bricks = so 64 on outer side....rest top side will be covered by wall....and also the sides will be covered by other walls....so 64 is sufficient

Re: There are 64 big cube-shaped bricks painted with yellow. How many smal   [#permalink] 06 Oct 2018, 11:07
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