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Is x = 5?

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Is x = 5? [#permalink]

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New post 14 Aug 2017, 06:18
1
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A
B
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D
E

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  35% (medium)

Question Stats:

45% (00:33) correct 55% (00:36) wrong based on 85 sessions

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Re: Is x = 5? [#permalink]

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New post 14 Aug 2017, 06:43
From A x = 0 or x = 5 not sufficient
From B x = 0 or x = -5
So sufficient B.
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Re: Is x = 5? [#permalink]

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New post 14 Aug 2017, 07:37
Bunuel wrote:
Is x = 5?

(1) \(x^2-5x=0\)

(2) \(2x^2+10x=0\)


Is x=5?

(1) \(x^2-5x=0\) --> \(x(x-5)=0\) --> \(x=0\) OR \(x=5\). Not sufficient, to answer whether \(x=5\).

(2) \(2x^2+10x=0\) --> \(x(x+5)=0\) --> \(x=0\) OR \(x=-5\). Here we know that \(x\neq{5}\), hence sufficient.

Answer: B.
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Re: Is x = 5? [#permalink]

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New post 24 Aug 2017, 13:37
Bunuel wrote:
Is x = 5?

(1) \(x^2-5x=0\)

(2) \(2x^2+10x=0\)


We need to determine whether x = 5.

Statement One Alone:

x^2 - 5x = 0

x^2 - 5x = 0

x(x - 5) = 0

x = 0 or x = 5

Since x could be either 0 or 5, statement one is not sufficient to answer the question.

Statement Two Alone:

2x^2 + 10x = 0

2x^2 + 10x = 0

2x(x + 5) = 0

x = 0 or x = - 5

Since x could be either 0 or -5, x will never equal 5. Statement two is sufficient to answer the question.

Answer: B
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Re: Is x = 5? [#permalink]

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New post 26 Aug 2017, 03:35
B. As we know it will not be 5. Statement 1 gives 0,5 (insufficient)


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Re: Is x = 5?   [#permalink] 26 Aug 2017, 03:35
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