m is less than

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m is less than

by sanju09 » Mon Feb 22, 2010 2:18 am
Square roots of two successive positive integers, each greater than n^2 (n ≠ 0), differ by m, then m is less than
(A) 1/ (2 n)
(B) 1/n
(C) 2/n
(D) 3/n
(E) 4/n
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by ajith » Mon Feb 22, 2010 3:13 am
sanju09 wrote:Square roots of two successive positive integers, each greater than n^2 (n ≠ 0), differ by m, then m is less than
(A) 1/ (2 n)
(B) 1/n
(C) 2/n
(D) 3/n
(E) 4/n
let the successive integers be k and k +1

sqrt(k) >n

m = sqrt(k+1) - sqrt(k)

=(sqrt(k+1) - sqrt(k))*(sqrt(k) + sqrt(k+1))/(sqrt(k) + sqrt(k+1))
= 1/(sqrt(k) + sqrt(k+1))
<1/(n+n)
<1/2n

[spoiler]A
[/spoiler]
Last edited by ajith on Mon Feb 22, 2010 4:25 am, edited 5 times in total.
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by sanju09 » Mon Feb 22, 2010 3:23 am
ajith wrote:
sanju09 wrote:Square roots of two successive positive integers, each greater than n^2 (n ≠ 0), differ by m, then m is less than
(A) 1/ (2 n)
(B) 1/n
(C) 2/n
(D) 3/n
(E) 4/n
let the successive integers be m and m+1

sqrt(m) >n

sqrt(m+1) - sqrt(m+1)

=(sqrt(m+1) - sqrt(m+1))*(sqrt(m+1) - sqrt(m+1))/(sqrt(m+1) + sqrt(m+1))
= 1/(sqrt(m+1) + sqrt(m+1))
<1/(n+n)
<1/2n

[spoiler]A
[/spoiler]
Won't the item in bold be zero?
The mind is everything. What you think you become. -Lord Buddha



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www.manyagroup.com

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by ajith » Mon Feb 22, 2010 3:38 am
sanju09 wrote:
Won't the item in bold be zero?
Copy paste errors - Fixed in the original post, thanks for pointing out, you know that logic was right!
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by sanju09 » Mon Feb 22, 2010 3:47 am
ajith wrote:
sanju09 wrote:Square roots of two successive positive integers, each greater than n^2 (n ≠ 0), differ by m, then m is less than
(A) 1/ (2 n)
(B) 1/n
(C) 2/n
(D) 3/n
(E) 4/n
let the successive integers be k and k +1

sqrt(k) >n

m = sqrt(k+1) - sqrt(k)

=(sqrt(k+1) - sqrt(k))*(sqrt(k+1) + sqrt(k+1))/(sqrt(k+1) + sqrt(k+1))
= 1/(sqrt(k+1) + sqrt(k+1))
<1/(n+n)
<1/2n

[spoiler]A
[/spoiler]
Characters changed yet character remains!
The mind is everything. What you think you become. -Lord Buddha



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by ajith » Mon Feb 22, 2010 4:24 am
sanju09 wrote: Characters changed yet character remains!
Edited again!

I am so happy that they have objective type questions in GMAT
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by sanju09 » Mon Feb 22, 2010 4:38 am
ajith wrote:
sanju09 wrote: Characters changed yet character remains!
Edited again!

I am so happy that they have objective type questions in GMAT
The titanic cost of pretty few things is never minded, HAPPINESS is one of these
The mind is everything. What you think you become. -Lord Buddha



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by ajith » Mon Feb 22, 2010 4:41 am
sanju09 wrote: The titanic cost of pretty few things is never minded, HAPPINESS is one of these
Ahem! Let us not digress!
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