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

I have my doubts between C and E.

A) n < 8
Not a must, because n still can be 8, 9 or 10
B) n = -6
Not a must, because n still can be -5 till 10
D) -10 < n < 7
Not a must because n still can be 7, 8, 9 or 10

C) n > -8
Yes it must be greater than -8, but we still have -7 which is not valid for n.

Hmmmm, I would pick E as answer.

Please correct me if I am wrong.

Regards,

Alex

It's questions like these that make one wonder what is this exam really testing. I'll bet the answer if C because the question doesn't ask if the answer choice will fall within the established perameters. It only asks which must be true and all numbers in that set will be greater than -8. It stinks but I think the answer is C.

-6<= n <= 10


this may sound really stupid for me to ask.. but what if n = -7..

-7 > -8 right??

As the saying goes, "there are no stupid questions" period.
We already know that n>=-6. So n cannot be =-7.

n can be -6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10
Looking at answer choices
1: n<8, False as n can be any value less than -6
2: n = -6 True as possible value
3: n>-8, False as n can be -7 which is incorrect
4: -10<n<7, False as n can be -9, -8,-7 which is incorrect
5: Not possible as (2) is correct.

The OA marked is impossible with the question given.
What is the source of question?

Thanks for correcting on this one.
It appears that interpreting the question is more than half the battle won.
In the answer choice (C), there is a tendency in this one to take a value of -7 & mark this choice as incorrect. However, if you look at the larger set of -6=<n=<10, then all the values of n here are greater than -8.

Cheers

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.

what about -7? n=-7 is not in the range of values mentioned for n

will go with E

kp1811,

I think your interpretation of the question is incorrect.

Let's revisit the question.

If it is true that –6 <= n <= 10, which of the following must be true?

In other words... if the value of n is given to be -6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10 which of the following must be true.

Can you infer/say with 100% confidence that all given values of n are greater than -8?

Hope this helps you.

agdimple333,

If you tell me that you took the GMAT 3 times and each time you scored between 710 and 770, and I say "Wow! you scored above 700 each time", will my statement always be true?

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 [highlight]must be true[/highlight]?

'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.

1. n<8?

n=9 no

n=-6 yes

not true all the time.
2. n=-6

not true all the time as -6<=n<=10

3. n>-8

even minimum value in the range -6<=n<=10, i.e n=-6>-8

so n>-8 all the time. In other words n>-8 must be true.

Answer is C.

There appears to be a very simple way to understand this problem...Popped into my head after seeing the tedious ways of making all understand, so thought of posting it.

Whenever you see a MUST BE TRUE question of the form IF [X], then [Y] MUST BE TRUE
Visualize/draw as a VENN DIAGRAM the above two conditions X and Y....In this case :

Fact : –6 <= n <= 10 ------- (X)

All the Other Choice -------- (Y)

When will this be a MUST BE TRUE ?

When X is always contained inside Y/ Y is equal to or a superset of Y

Now, you have got this idea....Just plug in the choices for Y putting X constant.

n < 8 fails for n < -6 and –6 <= n <= 10 n = –6 fails for all values when n <> -6 and –6 <= n <= 10 n > –8 does not fail for any value when n > –8 and –6 <= n <= 10 -10 < n < 7 fails for all values when n = -9,-8,-7 and and –6 <= n <= 10 none of the above

Hope this helps all !!!

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 !

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.