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If it is true that m^2 < 9 and m > -1, which of the following must be

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If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post Updated on: 13 Sep 2014, 06:45
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If it is true that m^2 < 9 and m > -1, which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

I believe the answer should be -1<m<3, however the answer key says m>-3.

Could someone explain this ?

Originally posted by madhavmarda on 12 Sep 2014, 22:41.
Last edited by Bunuel on 13 Sep 2014, 06:45, edited 1 time in total.
Renamed the topic and edited the question.
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 13 Sep 2014, 06:55
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madhavmarda wrote:
If it is true that m^2 < 9 and m > -1, which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

I believe the answer should be -1<m<3, however the answer key says m>-3.

Could someone explain this ?


m^2 < 9 means that -3 < m < 3. Combined with m > -1, we get that -1 < m < 3. Any m from this range must be greater than -3, hence A must be true.

Answer: A.
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If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 13 Sep 2014, 07:03
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madhavmarda wrote:
If it is true that \(m^2 < 9\) and \(m > -1\), which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

The question tells us \(m^2 < 9\), which simplifies to \(-3 < m < 3\).

We are also told that \(m > -1\). Combining the two conditions we get, \(-1 < m < 3\).

Now the question asks, what must be true. Let's look at the answer choices one at a time.

(A) \(m > -3\) ---- Since \(m > -1\), this will always be true. We have our answer and can stop right here. But let's look at the other answer choices just to be certain.

(B) \(m > 1\) ---- Not necessary. \(m\) can be \(0\).

(C) \(m > 3\) ---- False. \(m\) can never be more than \(3\).

(D) \(m < 1\) ---- Not necessary. \(m\) can be \(1\).

(E) None of the above ---- False, as we have already seen A is true.

So, the answer is A.

Hope that helps.
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If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 16 Nov 2014, 12:34
Bunuel wrote:
madhavmarda wrote:
If it is true that m^2 < 9 and m > -1, which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

I believe the answer should be -1<m<3, however the answer key says m>-3.

Could someone explain this ?


m^2 < 9 means that -3 < m < 3. Combined with m > -1, we get that -1 < m < 3. Any m from this range must be greater than -3, hence A must be true.

Answer: A.


How m > -3 satisfy the must be true criteria.

Consider m = +4 does it satisfy?
-1 < m < 3

Should be E) None of the above.
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 16 Nov 2014, 12:38
1
1
kinjiGC wrote:
Bunuel wrote:
madhavmarda wrote:
If it is true that m^2 < 9 and m > -1, which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

I believe the answer should be -1<m<3, however the answer key says m>-3.

Could someone explain this ?


m^2 < 9 means that -3 < m < 3. Combined with m > -1, we get that -1 < m < 3. Any m from this range must be greater than -3, hence A must be true.

Answer: A.


How m > -3 satisfy the must be true criteria.

Consider m = +4 does it satisfy?
-1 < m < 3

Should be E) None of the above.


The correct answer is A, not E. You misinterpreted the question. We are given that that -1 < m < 3. If -1 < m < 3, then it must be true that m is greater than -3.
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 16 Nov 2014, 22:47
since m^2>9
-3<m<3

given that m>-1

from both of these inequalities

m must be m>-3

Answer is A
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 23 May 2017, 05:39
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 25 Dec 2017, 20:56
madhavmarda wrote:
If it is true that m^2 < 9 and m > -1, which of the following must be true?

(A) m > -3
(B) m>1
(C) m>3
(D) m<1
(E) None of the above

I believe the answer should be -1<m<3, however the answer key says m>-3.

Could someone explain this ?


Check other similar questions from Trickiest Inequality Questions Type: Confusing Ranges (part of our Special Questions Directory).
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 03 Jan 2018, 14:27
For Beginners
if m^2<9
= m^2-9<0
=(m-3)(m+3)<0
:- The roots are +3 and -3
so the range is -3<x<3 As per the Wavvy line method( don't get carried away by this Jargon just search for the keyword wavvy ,it is an easy concept of quadratic Inequlaity which you should be aware of )
and the range is also m>-1
combined together the intersection region in the number line is
-1<x<3 is the final range

Now Analyze each answer choices

(A) m > -3
The Option A is always correct, because for any number in the range -1<x<3 is always greater than -3

(B) m>1
The Option B is not always correct for any number in the range -1<x <3, because there are also numbers less than 1 in the range

(C) m>3
The Option C is always wrong because we have the range as -1<x <3

(D) m<1
The Option D is not always correct for any number in the range -1<x <3, because there are also numbers greater than 1 in the range


(E) None of the above


Answer is A
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be  [#permalink]

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New post 03 Jan 2018, 20:27
m^2<9 -> -3<m<3
AND m>-1
Therefore -1<m<3
m>-3 is true to all m that satisfies the above inequality.
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Re: If it is true that m^2 < 9 and m > -1, which of the following must be &nbs [#permalink] 03 Jan 2018, 20:27
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If it is true that m^2 < 9 and m > -1, which of the following must be

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