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If xy = 2, xz = 8, and yz = 5, then the value of xyz is

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Intern
Joined: 22 Mar 2013
Posts: 11
Followers: 0

Kudos [?]: 0 [0], given: 15

If xy = 2, xz = 8, and yz = 5, then the value of xyz is [#permalink]  27 Jun 2013, 13:12
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Difficulty:

25% (medium)

Question Stats:

83% (01:36) correct 17% (00:44) wrong based on 29 sessions
If xy = 2, xz = 8, and yz = 5, then the value of xyz is closest to:

A. 5
B. 9
C. 15
D. 25
E. 75

My question is, why are there not two solutions to the problem?
I see that (x^2)(y^2)(z^2) = 80.

[Reveal] Spoiler: OA

Last edited by Bunuel on 27 Jun 2013, 13:22, edited 3 times in total.
Edited the question and moved to PS forum.
Math Expert
Joined: 02 Sep 2009
Posts: 27215
Followers: 4228

Kudos [?]: 41022 [1] , given: 5654

Re: If xy = 2 , xz = 8 , and yz = 5, then the value of xyz is [#permalink]  27 Jun 2013, 13:26
1
KUDOS
Expert's post
tmipanthers wrote:
If xy = 2, xz = 8, and yz = 5, then the value of xyz is closest to:

A. 5
B. 9
C. 15
D. 25
E. 75

My question is, why are there not two solutions to the problem?
I see that (x^2)(y^2)(z^2) = 80.

You are not making any error, xyz CAN be $$\sqrt{80}$$ as well as $$-\sqrt{80}$$.
_________________
Re: If xy = 2 , xz = 8 , and yz = 5, then the value of xyz is   [#permalink] 27 Jun 2013, 13:26
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