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study
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[5 ^ k] - [5 ^ (k-1)] Updated on: 17 Nov 2008, 02:52
Originally posted by study on 16 Nov 2008, 09:19.
Last edited by study on 17 Nov 2008, 02:52, edited 1 time in total.
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How do you solve for this?

[5 ^ k] - [5 ^ (k-1)]

Do not have the AC - only have the OA, will post it later.



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[5 ^ k] - [5 ^ (k-1)] 16 Nov 2008, 10:08
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study
How do you solve for this?

5^k - 5 ^k-1

Do not have the AC - only have the OA, will post it later.
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5^(k-1)(5-1) =4*5^(k-1)
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[5 ^ k] - [5 ^ (k-1)] 17 Nov 2008, 00:56
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study
How do you solve for this?

5^k - 5 ^k-1

Do not have the AC - only have the OA, will post it later.
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Study,

Can you please put brackets when you post such questions?
Though this problem is pretty straightforward, putting the brackets makes it much easier for folks to understand the problem.
It will also help you to get much faster response.
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[5 ^ k] - [5 ^ (k-1)] Updated on: 17 Nov 2008, 04:13
Originally posted by study on 17 Nov 2008, 02:28.
Last edited by study on 17 Nov 2008, 04:13, edited 1 time in total.
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Agreed.

Thanks for your suggestion. have edited the qs accordingly
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[5 ^ k] - [5 ^ (k-1)] 17 Nov 2008, 02:37
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study
I post questions exactly the way they are presented. I prefer not to alter the original qs, which could possibly alter its interpretation.
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I am not asking you to alter original Q.
What I wanted to say is that, when you see, say 2^(3+x) on gmat
it is clear to you that it is \(2^(3+x)\), but when you post on forum it may look like (2^3)+ x. If you avoid such a confusion it wont make the question ambiguous.
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[5 ^ k] - [5 ^ (k-1)] 17 Nov 2008, 09:17
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you neeed to factor the power so that you can manipulate easily..

say you have 5^x and 5^x-1 then if you factor (5^x-1) *5^1=5^x
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[5 ^ k] - [5 ^ (k-1)] 17 Nov 2008, 10:17
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Thanks fresinha...
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[5 ^ k] - [5 ^ (k-1)] 17 Nov 2008, 12:49
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How do you solve for this?

5^k - 5 ^k-1

Do not have the AC - only have the OA, will post it later.


5^(k-1)(5-1) =4*5^(k-1)
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I don't understand where the (5-1) comes from...


I get it.. after 40 mins.. Jeez



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Hi there,
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