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If it is true that -6 =< n =<10, which of the

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Re: Problem solving - inequality - 700 level [#permalink] New post 08 Aug 2011, 22:49
callingsid wrote:
when n > -8 then n = -7 (can be) the criterai -6<=n is not met here


Hi callingsid,
You are mis-interpreting the question. It's actually the other way round.

What we know is true : -6 <= n <= 10
i.e. n >= -6 and n <=10
When n> -6 , n is definitely > -8 .
n cannot be -7 , as n >= -6 is given to be true !
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Re: PS - KpE - 6 [#permalink] New post 06 Oct 2011, 00:30
hello guys,

I still cannot understand why the right answer is C. I chose E.
The question asks what must be true. So, as I understand it, the answer must be true in any situations.

The question states that -6 =< n =<10.
The right answer: n > –8 . It means that n can be equal to -7, isn't it?
It looks like the answer contradict the questions.

Can anybody explain me the logic behind the question?

The official explanation doesn't help much:

Analyze the Question:
In this question we are told that n is between -6 and 10 which limits our options for variables.

Identify the Task:
We need to attack each answer choice strategically looking for the answer choice that must be true and eliminating ones that may not be true.

Approach Strategically:
We should start with answer choice (D) and move up the choices to see if any must be true. If answers (A) through (D) are false or only could be true, we would choose answer choice(E). Choice (D) may be true, but if 7 ≤ n ≤ 10 then this statement is not true. Choice (C) must be true because all possible values of n specified by the inequality in the question stem are greater than -8, -8 < -6 ≤ n ≤ 10. We can stop here. Answer Choice (C) is correct.

Confirm your Answer:
Since the correct answer choice must be true, wrong answer choices are either false or could be true.
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Re: Problem solving - inequality - 700 level [#permalink] New post 06 Dec 2013, 06:30
VeritasPrepKarishma wrote:
shashankp27 wrote:
bschool83 wrote:
agdimple333 and zuberahmed,

What if n = -5, 0, or 5? Then answer choice B (n = –6) will fall apart.

–6 <= n <= 10 means all values between and equal to -6 and 10.

Answer choice C, n > –8 holds true for all available values of n. Hence answer is C.



how does it 'fall apart' ? could you please elaborate...


Focus on the question's wording:
If it is true that –6 <= n <= 10, which of the following must be true?

'must be true' implies that no matter what value n takes (out of the given range), 'which of the following will definitely hold?'
We have to find that option that will remain true. It is different from 'which of the following CAN be true?' i.e. which of the following is possible...
Given -6 <= n <= 10

n = -6 is possible. But it will not hold for all possible values of n i.e. if n = 5, then n is not equal to -6. So 'n = -6' is not a 'must be true' condition.

On the other hand, n > -8 will always be true.
If n = -6, then n > -8
If n = 0, then n > -8
If n = 4, then n > -8
If n = 10, then n > -8
Hope you got the point. No matter which value n takes out of the available values, n > -8 will always be true. For every value of n, n will be more than -8.
Therefore, answer will be C.

GMAT loves to lay this trap. Be very careful. Make sure you understand exactly what the question is asking.


Thank you for the explanation. I have a question if it says n>-8 could it also mean that n could anywhere between-8 and infinity. However the stem sayd that n is less than 10. Hence I got a little confused. Could you please clarify?
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Re: Problem solving - inequality - 700 level [#permalink] New post 06 Dec 2013, 07:17
Expert's post
Sam1 wrote:
VeritasPrepKarishma wrote:
shashankp27 wrote:
how does it 'fall apart' ? could you please elaborate...


Focus on the question's wording:
If it is true that –6 <= n <= 10, which of the following must be true?

'must be true' implies that no matter what value n takes (out of the given range), 'which of the following will definitely hold?'
We have to find that option that will remain true. It is different from 'which of the following CAN be true?' i.e. which of the following is possible...
Given -6 <= n <= 10

n = -6 is possible. But it will not hold for all possible values of n i.e. if n = 5, then n is not equal to -6. So 'n = -6' is not a 'must be true' condition.

On the other hand, n > -8 will always be true.
If n = -6, then n > -8
If n = 0, then n > -8
If n = 4, then n > -8
If n = 10, then n > -8
Hope you got the point. No matter which value n takes out of the available values, n > -8 will always be true. For every value of n, n will be more than -8.
Therefore, answer will be C.

GMAT loves to lay this trap. Be very careful. Make sure you understand exactly what the question is asking.


Thank you for the explanation. I have a question if it says n>-8 could it also mean that n could anywhere between-8 and infinity. However the stem sayd that n is less than 10. Hence I got a little confused. Could you please clarify?


The stem says that -6\leq{n}\leq{10}. Any value of n from this range (any value of n possible) is greater than -8. Thus C is always true.

Hope it's clear.
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Re: Problem solving - inequality - 700 level [#permalink] New post 06 Dec 2013, 09:03
Bunuel"[quote="VeritasPrepKarishma wrote:
shashankp27 wrote:
how does it 'fall apart' ? could you please elaborate...


Focus on the question's wording:
If it is true that –6 <= n <= 10, which of the following must be true?

'must be true' implies that no matter what value n takes (out of the given range), 'which of the following will definitely hold?'
We have to find that option that will remain true. It is different from 'which of the following CAN be true?' i.e. which of the following is possible...
Given -6 <= n <= 10

n = -6 is possible. But it will not hold for all possible values of n i.e. if n = 5, then n is not equal to -6. So 'n = -6' is not a 'must be true' condition.

On the other hand, n > -8 will always be true.
If n = -6, then n > -8
If n = 0, then n > -8
If n = 4, then n > -8
If n = 10, then n > -8
Hope you got the point. No matter which value n takes out of the available values, n > -8 will always be true. For every value of n, n will be more than -8.
Therefore, answer will be C.

GMAT loves to lay this trap. Be very careful. Make sure you understand exactly what the question is asking.


Thank you for the explanation. I have a question if it says n>-8 could it also mean that n could anywhere between-8 and infinity. However the stem sayd that n is less than 10. Hence I got a little confused. Could you please clarify?[/quote]

The stem says that -6\leq{n}\leq{10}. Any value of n from this range (any value of n possible) is greater than -8. Thus C is always true.

Hope it's clear.[/quote]
yes it does. Thank you.
Re: Problem solving - inequality - 700 level   [#permalink] 06 Dec 2013, 09:03
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