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# If the length of an edge of cube X is twice the length of an

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If the length of an edge of cube X is twice the length of an  [#permalink]

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07 Mar 2014, 04:46
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88% (00:45) correct 12% (01:05) wrong based on 611 sessions

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The Official Guide For GMAT® Quantitative Review, 2ND Edition

If the length of an edge of cube X is twice the length of an edge of cube Y, what is the ratio of the volume of cube Y to the volume of cube X?

(A) 1/2
(B) 1/4
(C) 1/6
(D) 1/8
(E) 1/27

Problem Solving
Question: 139
Category: Geometry Volume
Page: 80
Difficulty: 550

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Re: If the length of an edge of cube X is twice the length of an  [#permalink]

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07 Mar 2014, 04:46
SOLUTION

If the length of an edge of cube X is twice the length of an edge of cube Y, what is the ratio of the volume of cube Y to the volume of cube X?

(A) 1/2
(B) 1/4
(C) 1/6
(D) 1/8
(E) 1/27

The length of cube Y = 1;
The length of cube X = 2;

The ratio of the volume of cube Y to the volume of cube X = 1^3/2^3 = 1/8.

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Re: If the length of an edge of cube X is twice the length of an  [#permalink]

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07 Mar 2014, 05:27
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Let Y's edge be a. Then X's edge is 2a.

Y's volume = a^3
X's volume = (2a)^3 = 8(a^3)

Ratio Y's volume to X's volume = 1/8

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Re: If the length of an edge of cube X is twice the length of an  [#permalink]

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07 Mar 2014, 18:28
1
Option D.
Let side of X=2
Side of Y=1
Volume of cube=(side)^3
Vol. Y=1
Vol. X=8
Ratio=1/8

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Re: If the length of an edge of cube X is twice the length of an  [#permalink]

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13 Jun 2016, 12:44
Consider side(edge) of cube Y as 1 and side(edge) of cube X as 2
Volume of cube Y = $$1^3$$ = 1
Volume of cube X = $$2^3$$ = 8
Ratio = $$\frac{1}{8}$$

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Re: If the length of an edge of cube X is twice the length of an edge of  [#permalink]

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06 Dec 2017, 08:04
length of edge of cube x = 2a
length of edge of cube y = a

Ratio of volume y / volume x = {(length of edge of cube y)/(length of edge of cube x)}^3 = 1/8 . Hence answer is D.
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Re: If the length of an edge of cube X is twice the length of an edge of  [#permalink]

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06 Dec 2017, 08:50
Bunuel wrote:
If the length of an edge of cube X is twice the length of an edge of cube Y, what is the ratio of the volume of cube Y to the volume of cube X?

(A) 1/2
(B) 1/4
(C) 1/6
(D) 1/8
(E) 1/27

Let Length of edge of cube Y be 1, so edge of cube X is 2
Volume of Cube Y = 1 & Volume of Cube X = 8

So,ratio of the volume of cube Y to the volume of cube X is $$\frac{1}{8}$$, thus answer will be (D)

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Re: If the length of an edge of cube X is twice the length of an edge of  [#permalink]

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06 Dec 2017, 08:54
Bunuel wrote:
If the length of an edge of cube X is twice the length of an edge of cube Y, what is the ratio of the volume of cube Y to the volume of cube X?

(A) 1/2
(B) 1/4
(C) 1/6
(D) 1/8
(E) 1/27

Let Length of edge of cube Y be 1, so edge of cube X is 2
Volume of Cube Y = 1 & Volume of Cube X = 8

So,ratio of the volume of cube Y to the volume of cube X is $$\frac{1}{8}$$, thus answer will be (D)

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Thanks and Regards

Abhishek....

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Re: If the length of an edge of cube X is twice the length of an edge of  [#permalink]

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06 Dec 2017, 21:58
Let the edge of Cube Y = p
so as per the question the edge of Cube X = 2p

as we know the edge of cube Y is p so its volume is = p^3
similarly as we know the edge of cube X is 2p so its volume is = (2p)^3 = 8p^3

so what is asked in the question is the ratio of Volume of cube Y to Volume of cube X that is = (p^3/8p^3) ---> 1/8

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Re: If the length of an edge of cube X is twice the length of an  [#permalink]

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Re: If the length of an edge of cube X is twice the length of an   [#permalink] 23 Aug 2018, 02:05
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