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# (x^2 - 9)/3

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(x^2 - 9)/3 [#permalink]  26 Jun 2017, 01:44
Expert's post
00:00

Question Stats:

76% (00:47) correct 23% (01:29) wrong based on 17 sessions

GIVEN X>4

 Quantity A Quantity B $$\large{[\frac{(x^2 - 9)/3}{(x+3)/8}]\large}^{-1}$$ $$\frac{3}{8}$$

A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
[Reveal] Spoiler: OA

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Re: (x^2 - 9)/3 [#permalink]  26 Jul 2017, 15:28
1
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Can anyone help me with this question?
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Re: (x^2 - 9)/3 [#permalink]  21 Sep 2017, 09:32
As stated the expression above should be equal to $$[\frac{x^2-9}{3}*\frac{8}{x+3}]^{-1} = [\frac{(x-3)(x+3)}{3}*\frac{8}{x+3}]^{-1} = [\frac{(x-3)}{3}*8]^{-1} = \frac{3}{8}*\frac{1}{x-3}$$. Thus, the answer is uncertain since $$\frac{1}{x-3}$$ can be 1 making the two expression equal but also greater or lower than 1. How can the answer be B?
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Re: (x^2 - 9)/3 [#permalink]  21 Sep 2017, 20:54
Expert's post
$$\large[\frac{\frac{x+3}{8}}{\frac{(x^2 - 9)}{3}}\large]^{1}$$

The first quantity is raised to -1, then switch it in the reverse form.

$$\frac{3(x+3)}{8(x+3)(x-3)}$$

(x+3) cancel out

$$\frac{3}{8(x-3)}$$

Since x > 4, the denominator in Quantity A must be greater than 8; since the numerators in Quantity A and Quantity B are the same and the denominator in Quantity A is larger, Quantity B must be greater.

Hope now is clear
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Re: (x^2 - 9)/3 [#permalink]  22 Sep 2017, 19:20
how X>4; there is statement given that x>4. Ans is D
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Re: (x^2 - 9)/3 [#permalink]  22 Sep 2017, 21:40
Pria wrote:
how X>4; there is statement given that x>4. Ans is D

Question re aranged as per Source and X>4 (statement was missing) , Now corrected

Hope it helps

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Re: (x^2 - 9)/3   [#permalink] 22 Sep 2017, 21:40
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