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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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Archit3110 wrote:
Bunuel wrote:
Is x an integer?

(1) \(x^3 = 8\)
(2) \(x = \sqrt{4}\)

DS22602.01
OG2020 NEW QUESTION




Statement One Alone:

x^3 = 8

Since x^3 = 8, x = 2, then x is an integer.

Statement one alone is sufficient to answer the question.

Statement Two Alone:

x = √4

Since x = √4, x = 2, then x is an integer. (Recall that the square root symbol means to take the principal square root of a number, which is only the positive square root.)

Statement two alone is sufficient to answer the question.

Answer: D
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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Hi All,

We're asked if X is an INTEGER. This is a YES/NO question. This question is built around some standard math rules and Number Properties.

(1) X^3 = 8

With Fact 1, we're cubing the value of X and ending with a POSITIVE value - thus, X MUST be positive. Here, the value of X = +2 and the answer to the question is YES.
Fact 1 is SUFFICIENT

(2) X =√4

With Fact 1, we have a number that's square-rooted for the value of X. The square root of a number has just ONE solution: a POSITIVE one. Here, we're dealing with the positive square-root of 4, so the value of X = +2 and the answer to the question is YES.
Fact 2 is SUFFICIENT

Final Answer:

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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
X is an Integer?

Statement 1:\(X^3 = 8\)
This gives , X=2. Option A alone is sufficient

Statement 2: X = √4
This gives x=2 , Option B alone is sufficient

Ans: D
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
Bunuel. option B. according to Gmat, can we say that x!=2?
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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ShivamoggaGaganhs wrote:
Bunuel. option B. according to Gmat, can we say that x!=2?


Not sure I understand what yo mean but \(x = \sqrt{4}\) means that x = 2 only, nothing else.
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
Bunuel wrote:
Is x an integer?

(1) \(x^3 = 8\)
(2) \(x = \sqrt{4}\)

DS22602.01
OG2020 NEW QUESTION




Statement 1: x^3=8 > x has to be 2 which is an integer, note: x cannot be -2 as x^3 is equal to 8. SUFFICIENT
Statement 2: x=squareroot 4. Square root of 4 is (+)(-) 2, i.e it can be both positive and negative therefore integer. SUFFICIENT


Hope that helps!
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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hemantbafna wrote:
Bunuel wrote:
Is x an integer?

(1) \(x^3 = 8\)
(2) \(x = \sqrt{4}\)

DS22602.01
OG2020 NEW QUESTION




Statement 1: x^3=8 > x has to be 2 which is an integer, note: x cannot be -2 as x^3 is equal to 8. SUFFICIENT
Statement 2: x=squareroot 4. Square root of 4 is (+)(-) 2, i.e it can be both positive and negative therefore integer. SUFFICIENT


Hope that helps!


Hi hemantbafna,

You selected the correct answer, but there's a subtle rule here that you appear to have missed. On the GMAT, the result of a square root of a positive number can ONLY be positive. For example....

√4 = +2

However, a squared-term that equals a positive number can lead to a positive or negative result. For example...

X^2 = 4..... X = +2 or -2.

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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
Expert Reply
Bunuel wrote:
Is x an integer?

(1) \(x^3 = 8\)
(2) \(x = \sqrt{4}\)

DS22602.01
OG2020 NEW QUESTION


Wanna make solving the Official Questions interesting???


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Answer: Option D

Video solution by GMATinsight



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Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
x^3 = 8 actually has 3 solutions ;

\(x^3 - 8 =0\)
\((x-2)(x^2+2x+4)=0\)
1 for the above equation \(x=2\)
other 2 solutions are imaginary \( [-1+i\sqrt{3}], [-1-i\sqrt{3}]\)

so we cant say x is an interger or imaginary,
can someone please clarify.

Bunuel
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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Hi Kanna444,

Imaginary numbers are NOT a subject that the GMAT 'tests' - and that ultimately means that you are NOT expected to think in those terms when answering GMAT questions.

GMAT assassins aren't born, they're made,
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
Is x an integer?

(1) x^3=8

Since 8 is a perfect cube, we can easily say x = 2 (INTEGER)

(2) x=√4

Since √4 = +2, we can say that X is an integer

OPTION D
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
Bunuel bb EMPOWERgmatRichC

can you please clarify this case?

Kanna444 wrote:
x^3 = 8 actually has 3 solutions ;

\(x^3 - 8 =0\)
\((x-2)(x^2+2x+4)=0\)
1 for the above equation \(x=2\)
other 2 solutions are imaginary \( [-1+i\sqrt{3}], [-1-i\sqrt{3}]\)

so we cant say x is an interger or imaginary,
can someone please clarify.

Bunuel
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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vedha0 wrote:
Bunuel bb EMPOWERgmatRichC

can you please clarify this case?

Kanna444 wrote:
x^3 = 8 actually has 3 solutions ;

\(x^3 - 8 =0\)
\((x-2)(x^2+2x+4)=0\)
1 for the above equation \(x=2\)
other 2 solutions are imaginary \( [-1+i\sqrt{3}], [-1-i\sqrt{3}]\)

so we cant say x is an interger or imaginary,
can someone please clarify.

Bunuel
EMPOWERgmatRichC


On the GMAT, all numbers are assumed to be real numbers by default.
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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vedha0 wrote:
Bunuel bb EMPOWERgmatRichC

can you please clarify this case?

Kanna444 wrote:
x^3 = 8 actually has 3 solutions ;

\(x^3 - 8 =0\)
\((x-2)(x^2+2x+4)=0\)
1 for the above equation \(x=2\)
other 2 solutions are imaginary \( [-1+i\sqrt{3}], [-1-i\sqrt{3}]\)

so we cant say x is an interger or imaginary,
can someone please clarify.

Bunuel
EMPOWERgmatRichC


Hi vedha0,

Imaginary numbers are NOT a subject that the GMAT 'tests' - and that ultimately means that you are NOT expected to think in those terms when answering GMAT questions.

GMAT assassins aren't born, they're made,
Rich

Contact Rich at: Rich.C@empowergmat.com
www.empowergmat.com
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Re: Is x an integer? (1) x^3 = 8 (2) x = 4^(1/2) [#permalink]
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