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Equation

by N:Dure » Sat Dec 18, 2010 10:43 pm
If (x+5) root (1/x + 1/5) = 5, then x =

A) -5
B) 1/2
C) 1
D) 5
E) 10

Image
Last edited by N:Dure on Sun Dec 19, 2010 12:41 am, edited 2 times in total.
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by Geva@EconomistGMAT » Sun Dec 19, 2010 12:00 am
What does the root mean, in this equation? Is this a typo?
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by N:Dure » Sun Dec 19, 2010 12:08 am
This is the original question
Image
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by Geva@EconomistGMAT » Sun Dec 19, 2010 12:13 am
N:Dure wrote:This is the original question
Image
*shrug*
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by N:Dure » Sun Dec 19, 2010 12:15 am
Geva@MasterGMAT wrote:
N:Dure wrote:This is the original question
Image
*shrug*
lol!
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by jaymw » Sun Dec 19, 2010 12:26 am
Can you scan it?

Or use MS equation? It's included in word.

I tried to solve for what you wrote but it does not work for any of the answer choices. You'd end up with an equation of the form: ax³+bx²+cx+d=0, which is very uncommon on the GMAT.
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by N:Dure » Sun Dec 19, 2010 12:39 am
The image is in the 3rd post.

The source is Nova Math Bible

I also tried squaring both sides but to no use. Maybe it's just a wrong question
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by N:Dure » Sun Dec 19, 2010 8:23 am
Here's the OA, which I don't get either. Can someone pls explain the 3rd step?

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by Geva@EconomistGMAT » Sun Dec 19, 2010 8:26 am
N:Dure wrote:Here's the OA, which I don't get either. Can someone pls explain the 3rd step?

Image
No image/attachment here, or in the third one.
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by N:Dure » Sun Dec 19, 2010 8:41 am
hmm it's showing in your post.... maybe cause I'm logged in the forum I'm linking from. you have to be a member to see the images.

Both are attached now
Attachments
equation.png
screenshot21c..png
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by diebeatsthegmat » Sun Dec 19, 2010 5:46 pm
N:Dure wrote:hmm it's showing in your post.... maybe cause I'm logged in the forum I'm linking from. you have to be a member to see the images.

Both are attached now
this is insane! :(
how come (x+5)*V(1/x+1/5)=(x+5)(5x/(x+5)????
(1/x+1/5) is in a squroot, how come it suddenly be equal to 5x/(x+5)???????
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by anshumishra » Sun Dec 19, 2010 6:17 pm
Probably the question is :

(x+5)/(1/x+1/5) = 5 and not
(x+5)sqrt(1/x+1/5) = 5

:D
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by showbiz » Mon Dec 20, 2010 7:42 pm
diebeatsthegmat wrote:
N:Dure wrote:hmm it's showing in your post.... maybe cause I'm logged in the forum I'm linking from. you have to be a member to see the images.

Both are attached now
this is insane! :(
how come (x+5)*V(1/x+1/5)=(x+5)(5x/(x+5)????
(1/x+1/5) is in a squroot, how come it suddenly be equal to 5x/(x+5)???????
I agree....it is insane :D
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