Last visit was: 25 Apr 2024, 18:18 It is currently 25 Apr 2024, 18:18

Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Tags:
Show Tags
Hide Tags
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6820
Own Kudos [?]: 29931 [63]
Given Kudos: 799
Location: Canada
Send PM
Most Helpful Reply
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6820
Own Kudos [?]: 29931 [14]
Given Kudos: 799
Location: Canada
Send PM
Current Student
Joined: 13 Apr 2015
Posts: 1436
Own Kudos [?]: 4548 [10]
Given Kudos: 1228
Location: India
Send PM
General Discussion
avatar
Intern
Intern
Joined: 07 Oct 2015
Posts: 6
Own Kudos [?]: 1 [1]
Given Kudos: 2
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Kudos
GMATPrepNow wrote:
s1d1 wrote:
can anybody explain the answer?


Vyshak's solutions are great.
Let's examine his second approach.

If -2 < x < 5, then it's possible that x = 5, in which case x² = 25
In other words, it's possible that x² = 25
When we check the answer choices, we see that...
Answer choice A says that x² < 16. In other words, it says that x² cannot equal 25. ELIMINATE A
Answer choice C says that x² < 16. In other words, it says that x² cannot equal 25. ELIMINATE C

Also, if -2 < x < 5, then it's possible that x = 0, in which case x² = 0
In other words, it's possible that x² = 0
When we check the remaining answer choices, we see that...
Answer choice B says that 4 < x². In other words, it says that x² cannot equal 0. ELIMINATE B
Answer choice D says that 0 < x². In other words, it says that x² cannot equal 0. ELIMINATE D

We're left with 1 answer choice...E

Cheers,
Brent


Square of any number can never b negative, answer D is correct.
Math Expert
Joined: 02 Sep 2009
Posts: 92915
Own Kudos [?]: 619033 [1]
Given Kudos: 81595
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Bookmarks
Expert Reply
afarrukh786 wrote:
GMATPrepNow wrote:
s1d1 wrote:
can anybody explain the answer?


Vyshak's solutions are great.
Let's examine his second approach.

If -2 < x < 5, then it's possible that x = 5, in which case x² = 25
In other words, it's possible that x² = 25
When we check the answer choices, we see that...
Answer choice A says that x² < 16. In other words, it says that x² cannot equal 25. ELIMINATE A
Answer choice C says that x² < 16. In other words, it says that x² cannot equal 25. ELIMINATE C

Also, if -2 < x < 5, then it's possible that x = 0, in which case x² = 0
In other words, it's possible that x² = 0
When we check the remaining answer choices, we see that...
Answer choice B says that 4 < x². In other words, it says that x² cannot equal 0. ELIMINATE B
Answer choice D says that 0 < x². In other words, it says that x² cannot equal 0. ELIMINATE D

We're left with 1 answer choice...E

Cheers,
Brent


Square of any number can never b negative, answer D is correct.


From the stem x CAN be 0, and if it is, then D is wrong. The correct answer is E. Please re-read the solutions above.
avatar
Intern
Intern
Joined: 07 Oct 2015
Posts: 6
Own Kudos [?]: 1 [0]
Given Kudos: 2
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
From the stem x CAN be 0, and if it is, then D is wrong. The correct answer is E. Please re-read the solutions

D option does not say equal to zero, it says greater than zero, if you see option D, there is not a sign of equal to
avatar
Intern
Intern
Joined: 06 Oct 2016
Posts: 17
Own Kudos [?]: 4 [1]
Given Kudos: 0
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Kudos
I could agree with all of you and eliminate abcd but what about e square of any number cannot be negative so how is option e true.

Can anyone tell why option E.

Sent from my A1601 using GMAT Club Forum mobile app
avatar
Intern
Intern
Joined: 24 Oct 2016
Posts: 6
Own Kudos [?]: 1 [0]
Given Kudos: 0
Location: United States
GMAT 1: 750 Q48 V44
GPA: 3.2
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
ashishahujasham wrote:
I could agree with all of you and eliminate abcd but what about e square of any number cannot be negative so how is option e true.

Can anyone tell why option E.


This to me is a simple question that is complicated by GMAT trickery in the way the answer choices are presented. the smallest value for x^2 is 0, and 0 is always greater than -4, so option E still fulfills the demands of the question. It is always true that x^2 is greater than or equal to -4 because it is always greater than -4.
avatar
Intern
Intern
Joined: 07 Oct 2015
Posts: 6
Own Kudos [?]: 1 [0]
Given Kudos: 2
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
adamm412 wrote:
ashishahujasham wrote:
I could agree with all of you and eliminate abcd but what about e square of any number cannot be negative so how is option e true.

Can anyone tell why option E.


This to me is a simple question that is complicated by GMAT trickery in the way the answer choices are presented. the smallest value for x^2 is 0, and 0 is always greater than -4, so option E still fulfills the demands of the question. It is always true that x^2 is greater than or equal to -4 because it is always greater than -4.



How can E be answer while it include negative numbers and zero also
avatar
Intern
Intern
Joined: 24 Oct 2016
Posts: 6
Own Kudos [?]: 1 [1]
Given Kudos: 0
Location: United States
GMAT 1: 750 Q48 V44
GPA: 3.2
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Kudos
afarrukh786 wrote:
adamm412 wrote:
ashishahujasham wrote:
I could agree with all of you and eliminate abcd but what about e square of any number cannot be negative so how is option e true.

Can anyone tell why option E.


This to me is a simple question that is complicated by GMAT trickery in the way the answer choices are presented. the smallest value for x^2 is 0, and 0 is always greater than -4, so option E still fulfills the demands of the question. It is always true that x^2 is greater than or equal to -4 because it is always greater than -4.



How can E be answer while it include negative numbers and zero also


Again it comes down to the way the question is presented: "which of the following MUST be true". In theory, answer E could have been -1,000,000 ≤ x^2 < 1,000,000 and it would still be the only correct answer because it is the only solution offered that contains the actual possible values of x^2. notice the maximum value of x^2 is 25 but answer E allows for up to 36... we know x^2 cannot get that big, but the way the solution is presented means x^2 never actually needs to reach ~36 in order for it to still satisfy those constraints. This is the same idea on the negative lower bound of x^2.

Also, x^2 = 0 is a possible solution if x=0.
avatar
Manager
Manager
Joined: 06 Jun 2016
Posts: 233
Own Kudos [?]: 110 [3]
Given Kudos: 212
Location: India
Concentration: Operations, Strategy
Schools: ISB '18 (D)
GMAT 1: 600 Q49 V23
GMAT 2: 680 Q49 V34
GPA: 3.9
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
2
Kudos
1
Bookmarks
GMATPrepNow wrote:
If \(-2 < x \leq {5}\), then which of the following MUST be true?

A) \(-1 < x^2 < 16\)
B) \(4 < x^2 \leq {25}\)
C) \(0 \leq {x^2} \leq {16}\)
D) \(0 < x^2 \leq {25}\)
E) \(-4 \leq {x^2} < 36\)

Kudos for every correct solution.



Ok lets make it simpler. Given is \(-2 < x \leq {5}\)
which means x can have the following values -1, 0, 1, 2, 3, 4, 5 (for simplification purpose i'm using integers. x can have a decimal values also as question doesn't say x is an integer)
now see what all values can x^2 take. x^2 can take 0, 1, 4, 9, 16, 25. Yes?
with this knowledge approach the answer choice. Only option E gives you all the above values of x^2.
Math Expert
Joined: 02 Sep 2009
Posts: 92915
Own Kudos [?]: 619033 [1]
Given Kudos: 81595
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Bookmarks
Expert Reply
afarrukh786 wrote:
adamm412 wrote:
ashishahujasham wrote:
I could agree with all of you and eliminate abcd but what about e square of any number cannot be negative so how is option e true.

Can anyone tell why option E.


This to me is a simple question that is complicated by GMAT trickery in the way the answer choices are presented. the smallest value for x^2 is 0, and 0 is always greater than -4, so option E still fulfills the demands of the question. It is always true that x^2 is greater than or equal to -4 because it is always greater than -4.



How can E be answer while it include negative numbers and zero also


I think you don't understand the logic of the question. The question asks: if \(-2 < x \leq {5}\), then which of the following MUST be true? So, we KNOW that \(-2 < x \leq {5}\) and should evaluate which of the options must be correct. If \(-2 < x \leq {5}\), then only E must be true.
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11178
Own Kudos [?]: 31933 [2]
Given Kudos: 290
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
2
Kudos
Expert Reply
GMATPrepNow wrote:
If \(-2 < x \leq {5}\), then which of the following MUST be true?

A) \(-1 < x^2 < 16\)

B) \(4 < x^2 \leq {25}\)

C) \(0 \leq {x^2} \leq {16}\)

D) \(0 < x^2 \leq {25}\)

E) \(-4 \leq {x^2} < 36\)


Hi,
No calculations required, just logic on the choices given...

E has the widest range and contains ALL other choices, so if any of A to D is correct, E has to be correct....
But can we have TWO answers, No..
So E is the answer
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6820
Own Kudos [?]: 29931 [3]
Given Kudos: 799
Location: Canada
Send PM
If -2 < x <= 5, then which of the following MUST be true? [#permalink]
3
Kudos
Expert Reply
Top Contributor
GMATPrepNow wrote:
If \(-2 < x \leq {5}\), then which of the following MUST be true?

A) \(-1 < x^2 < 16\)

B) \(4 < x^2 \leq {25}\)

C) \(0 \leq {x^2} \leq {16}\)

D) \(0 < x^2 \leq {25}\)

E) \(-4 \leq {x^2} < 36\)


Many students will assume that E is incorrect, because x² CANNOT equal -4. However, answer choice E does not suggest that x² can equal -4, it only states that x² must be GREATER THAN or equal to -4.

Here's a similar example: If Joe has more than 5 shirts, which of the following can we conclude with certainty?
A) Joe owns more than 6 shirts.
NO. We can't conclude this, because it's possible that Joe owns exactly 6 shirts, and 6 is not greater than 6.

B) Joe owns more than -3 shirts.
YES. If Joe owns more than 5 shirts, then he definitely owns more than -3 shirts
Does this mean that Joe COULD own -2 shirts? No. If just means that we can be certain that he owns more than -3 shirts.

Does that help?

Cheers,
Brent

Originally posted by BrentGMATPrepNow on 20 Nov 2016, 06:35.
Last edited by BrentGMATPrepNow on 16 Nov 2020, 17:09, edited 1 time in total.
Intern
Intern
Joined: 06 Jul 2021
Posts: 10
Own Kudos [?]: 0 [0]
Given Kudos: 25
Location: India
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
I have to disagree with the solution here. E tells us that |x| is less that 6, which could imply x=5.99999 and so on. However the range is fixed from -2 to 5, and x is not necessarily an integer. If it was, I would have agreed with the solution (E).

For me, I choose D.
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11178
Own Kudos [?]: 31933 [1]
Given Kudos: 290
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
1
Kudos
Expert Reply
akankshasehgal16 wrote:
I have to disagree with the solution here. E tells us that |x| is less that 6, which could imply x=5.99999 and so on. However the range is fixed from -2 to 5, and x is not necessarily an integer. If it was, I would have agreed with the solution (E).

For me, I choose D.



The range is -2<x≤5

least value for x^2 is 0 when x is 0.
Maximum value for x^2 is 25 when x is 5.

So the actual range is 0 ≤ x ≤ 25.

Now D does not contain 0.

Only E contains this range
Intern
Intern
Joined: 04 Aug 2022
Posts: 21
Own Kudos [?]: 2 [0]
Given Kudos: 228
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
The question stem didn't say that we have to include all the values, it just says "must be true".

E's range starts from -4 to 36.

All the values fall within this range but we have extra values as well.

D's range starts from 0 to 25. This is 100% true. Every value falls within this range.

E makes less sense to me.
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32680
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: If -2 < x <= 5, then which of the following MUST be true? [#permalink]
Moderators:
Math Expert
92915 posts
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne