Approximately 90 percent of the volume of a certain cube that is float

Question

Approximately 90 percent of the volume of a certain cube that is floating in a tank of water is beneath the surface. If 6.4 cubic centimeters of the cube is above the surface of the water, what is the approximate length, in centimeters, of an edge of the cube?

A. 10
B. 8
C. 6
D. 4
E. 2

A. 10
B. 8
C. 6
D. 4
E. 2

PS21155

gvij2017 · Answer

6.4 = volume above water surface = (100-90% = 10% of cubic volume.)

Total volume = 64 = a^3 where a is side of cube.

a= 4 
D is answer.

Abhishek009 · Answer

Please check a must be = 4

GMATinsight · Answer

10% of cube volume = 6.4

Volume of Cube =  Side^3

i.e.  (10/100)*a^3 = 6.4

i.e.  a^3 = 64 
i.e. a ≈ 4

Answer: Option D

Archit3110 · Answer

area of exposed part of cube 
10/100 * x = 6.4
x = 64
x is area so x ^3 = 64 ; x= 4 ( edge length)
option D ;

gvij2017 · Answer

Thanks!

Corrected the error.

ScottTargetTestPrep · Answer

We see that 6.4 cubic cm of the cube is 10% of the volume of the cube. Therefore, the volume of the entire cube is 64 cubic cm, and hence its edge is 3^√64 = 4.

Answer: D

gmatchile · Answer

If 90% of a cube is below the surface, then 10% of the cube is above the surface.

So 10% of the volume of the cube is equal to 6.4 cubic centimeters.

Recall that the volume of a cube is its edge (A) cubed (Aexp3).

Then:

(10/100) x Aexp3 = 6.4
Aexp3 = 6.4 x 10

So A = the cube root of (6.4 x 10)
 = cube root of (64)

Then: 4 x 4 x4 = 64

A = 4

Answer D

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Approximately 90 percent of the volume of a certain cube that is float

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Approximately 90 percent of the volume of a certain cube that is float

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