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If d is a positive integer is d^1/2 an intger

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If d is a positive integer is d^1/2 an intger [#permalink]

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If \(d\) is a positive integer is \(\sqrt{d}\) an integer?

(1) \(d\) is the square of an integer
(2) \(\sqrt{d}\) is the square of an integer


[Reveal] Spoiler:
I have rephrased the question to basically state, is d a perfect square?

1) If d is the square of an integer this is saying that, an integer, when multiplied by itself = d --> Sufficient

2) I had a little trouble rephrasing this to be more understandable, can anybody clarify?
[Reveal] Spoiler: OA

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Re: Quant Review 2nd Edition: DS 115 [#permalink]

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New post 07 Nov 2010, 11:39
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Hi,

Correct me, If I am wrong,

Quote:
If d is a positive integer is \sqrt{d}an integer?


The Integer set contains, all the whole number and the negatives of all the natural number ie -1,-2,0,1,2

As per your statement, If Suppose 3 is a positive integer, \sqrt{3} will also be positive integer, which is not true as sqrt3 is approx 1.73, which by definition doesn't fall in integer set.

If & Only If d is a perfect square, the \sqrt{d} will a integer as in 121 will give +11, -11.

Do let me know, If I am missing something or mis-stated something.

Regards,
Tushar

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Re: Quant Review 2nd Edition: DS 115 [#permalink]

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jscott319 wrote:
If \(d\) is a positive integer is \(\sqrt{d}\)an integer?

1) \(d\) is the square of an integer
2) \(\sqrt{d}\) is the square of an integer


I have rephrased the question to basically state, is d a perfect square?

1) If d is the square of an integer this is saying that, an integer, when multiplied by itself = d --> Sufficient

2) I had a little trouble rephrasing this to be more understandable, can anybody clarify?


Given: \(d=integer\). Question: is \(\sqrt{d}=integer\)? or as you correctly rephrased is \(d\) a perfect square: is \(d=integer^2\)?

(1) \(d\) is the square of an integer --> \(d=integer^2\) --> directly gives an answer. Sufficient.
(2) \(\sqrt{d}\) is the square of an integer --> \(\sqrt{d}=integer^2=integer\) (as square of an integer is an integer). Sufficient.

Answer: D.

Similar questions:
i-cant-understand-how-the-oa-is-101475.html?hilit=irrational
algebra-ds-101464.html

Hope it helps.
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Re: Quant Review 2nd Edition: DS 115 [#permalink]

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New post 07 Nov 2010, 12:49
Thank you that does help. Not sure why I couldnt process it ha. Tricky wording. Thanks for the link as well +1

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Re: Quant Review 2nd Edition: DS 115 [#permalink]

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New post 07 Nov 2010, 15:07
Just put two values for positive integer variable D. For ex- D=15 or D=16.

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Re: If d is a positive integer is d^1/2 an intger [#permalink]

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New post 24 Nov 2017, 23:30
jscott319 wrote:
If \(d\) is a positive integer is \(\sqrt{d}\) an integer?

(1) \(d\) is the square of an integer
(2) \(\sqrt{d}\) is the square of an integer


[Reveal] Spoiler:
I have rephrased the question to basically state, is d a perfect square?

1) If d is the square of an integer this is saying that, an integer, when multiplied by itself = d --> Sufficient

2) I had a little trouble rephrasing this to be more understandable, can anybody clarify?


OPEN DISCUSSION OF THIS QUESTION IS HERE: https://gmatclub.com/forum/if-d-is-a-po ... 67950.html
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

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Re: If d is a positive integer is d^1/2 an intger   [#permalink] 24 Nov 2017, 23:30
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