Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score. Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions) Oct 23 08:00 AM PDT  09:00 AM PDT Join an exclusive interview with the people behind the test. If you're taking the GMAT, this is a webinar you cannot afford to miss! Oct 26 07:00 AM PDT  09:00 AM PDT Want to score 90 percentile or higher on GMAT CR? Attend this free webinar to learn how to prethink assumptions and solve the most challenging questions in less than 2 minutes. Oct 27 07:00 AM EDT  09:00 AM PDT Exclusive offer! Get 400+ Practice Questions, 25 Video lessons and 6+ Webinars for FREE.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58434

Question Stats:
54% (01:12) correct 46% (01:11) wrong based on 256 sessions
HideShow timer Statistics
If x is an integer and \(9 \lt x^2 \lt 99\), then what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)? A. \(5\) B. \(6\) C. \(7\) D. \(18\) E. \(20\)
Official Answer and Stats are available only to registered users. Register/ Login.
_________________



Math Expert
Joined: 02 Sep 2009
Posts: 58434

Re D0142
[#permalink]
Show Tags
16 Sep 2014, 00:13
Official Solution: If x is an integer and \(9 \lt x^2 \lt 99\), then what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)?A. \(5\) B. \(6\) C. \(7\) D. \(18\) E. \(20\) Notice that \(x\) can take positive, as well as negative values to satisfy \(9 \lt x^2 \lt 99\), hence \(x\) can be: 9, 8, 7, 6, 5, 4, 4, 5, 6, 7, 8, or 9. We are asked to find the value of x(max)x(min), and since x(max)=9 and x(min)=9 then x(max)x(min)=9(9)=18. Answer: D
_________________



Intern
Joined: 27 Apr 2014
Posts: 36

Re: D0142
[#permalink]
Show Tags
26 Dec 2014, 04:09
Bunuel wrote: Official Solution:
If x is an integer and \(9 \lt x^2 \lt 99\), then what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)?
A. \(5\) B. \(6\) C. \(7\) D. \(18\) E. \(20\)
Notice that \(x\) can take positive, as well as negative values to satisfy \(9 \lt x^2 \lt 99\), hence \(x\) can be: 9, 8, 7, 6, 4, 4, 5, 6, 7, 8, or 9. We are asked to find the value of x(max)x(min), and since x(max)=9 and x(min)=9 then x(max)x(min)=9(9)=18.
Answer: D but the questions is asking about x not x^2 though
_________________
Kudos my back and I Kudos your back



Math Expert
Joined: 02 Sep 2009
Posts: 58434

amenon55 wrote: Bunuel wrote: Official Solution:
If x is an integer and \(9 \lt x^2 \lt 99\), then what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)?
A. \(5\) B. \(6\) C. \(7\) D. \(18\) E. \(20\)
Notice that \(x\) can take positive, as well as negative values to satisfy \(9 \lt x^2 \lt 99\), hence \(x\) can be: 9, 8, 7, 6, 4, 4, 5, 6, 7, 8, or 9. We are asked to find the value of x(max)x(min), and since x(max)=9 and x(min)=9 then x(max)x(min)=9(9)=18.
Answer: D but the questions is asking about x not x^2 though The question asks what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)? x (not x^2) can be: 9, 8, 7, 6, 5, 4, 4, 5, 6, 7, 8, or 9: x(max)  x(min) = 9  (9) = 18.
_________________



Intern
Joined: 05 Jan 2015
Posts: 11
Location: India
Concentration: International Business, Marketing
WE: Engineering (Energy and Utilities)

Re: D0142
[#permalink]
Show Tags
02 Dec 2015, 22:39
amenon55 wrote: Bunuel wrote: Official Solution:
If x is an integer and \(9 \lt x^2 \lt 99\), then what is the value of maximum possible value of \(x\) minus minimum possible value of \(x\)?
A. \(5\) B. \(6\) C. \(7\) D. \(18\) E. \(20\)
Notice that \(x\) can take positive, as well as negative values to satisfy \(9 \lt x^2 \lt 99\), hence \(x\) can be: 9, 8, 7, 6, 4, 4, 5, 6, 7, 8, or 9. We are asked to find the value of x(max)x(min), and since x(max)=9 and x(min)=9 then x(max)x(min)=9(9)=18.
Answer: D but the questions is asking about x not x^2 though 9 < x^2 < 99 Take the square root of all sides. Now when you take the square root of a number you get a positive and a negative root: √9 = ±3 and √99 ≅ ±9.95. This produces two intervals for x: 9.95 < x < 3 and 3 < x < 9.95 Since x is an integer, its maximum value is x = 9 and its minimum value is x = 9 (Max Value of x)  (Min Value of x) = 9  (9) = 9 + 9 = 18



Intern
Joined: 09 Nov 2015
Posts: 4
GPA: 3.5
WE: Medicine and Health (Health Care)

Re: D0142
[#permalink]
Show Tags
10 Dec 2015, 03:48
I think this is a highquality question and the explanation isn't clear enough, please elaborate. since 9< x^2 < 99 means +/ 3 <x< +/10 (square root) therefore max minus min value would be +10  (3) which is 10 + 3 = 13. Please tell me where am i going wrong with my approach. thank you



Math Expert
Joined: 02 Sep 2009
Posts: 58434

Re: D0142
[#permalink]
Show Tags
12 Dec 2015, 08:38
Bhavanasg wrote: I think this is a highquality question and the explanation isn't clear enough, please elaborate. since 9< x^2 < 99 means +/ 3 <x< +/10 (square root) therefore max minus min value would be +10  (3) which is 10 + 3 = 13. Please tell me where am i going wrong with my approach. thank you Please read the thread above. Hope it helps.
_________________



Intern
Joined: 16 Feb 2016
Posts: 49
Concentration: Other, Other

Re: D0142
[#permalink]
Show Tags
26 Apr 2016, 23:58
Good question. Need to consider the negative values as well...



Intern
Joined: 09 Sep 2014
Posts: 1

Re: D0142
[#permalink]
Show Tags
16 Jul 2016, 12:36
x can take positive, as well as negative values
One should always consider all possible cases in mind.



Manager
Joined: 03 Dec 2013
Posts: 67
Location: United States (HI)
GPA: 3.56

Re: D0142
[#permalink]
Show Tags
22 Aug 2016, 12:48
I think this is a highquality question and I agree with explanation. GG. Well Played...



Intern
Joined: 12 May 2016
Posts: 7
Location: India
GPA: 3.93

Re: D0142
[#permalink]
Show Tags
02 Jan 2017, 04:59
I think this is a poorquality question and the explanation isn't clear enough, please elaborate. Since 9<x2 <99 so values of x should range
3,2,1,0,1,2,3,4,5,6,7,8,9



Math Expert
Joined: 02 Sep 2009
Posts: 58434

Re: D0142
[#permalink]
Show Tags
02 Jan 2017, 05:18
C3BISHT wrote: I think this is a poorquality question and the explanation isn't clear enough, please elaborate. Since 9<x2 <99 so values of x should range
3,2,1,0,1,2,3,4,5,6,7,8,9 I have to disagree. The question is correct and of a good quality. As for your doubt. If 9 < x^2 < 99 how can x be 3, 2, 1, or 0? The do not satisfy 9 < x^2 < 99. x can be: 9, 8, 7, 6, 4, 4, 5, 6, 7, 8, or 9.
_________________



Intern
Joined: 15 Oct 2016
Posts: 2

Re: D0142
[#permalink]
Show Tags
21 Feb 2017, 18:46
This is a highquality and "tricky" question.



Current Student
Joined: 28 Dec 2016
Posts: 88
Location: United States (IL)
Concentration: Marketing, General Management

Re: D0142
[#permalink]
Show Tags
27 May 2017, 12:28
Bunuel, Is there a reason why you skipped 5 among the possible values of x?



Math Expert
Joined: 02 Sep 2009
Posts: 58434

Re: D0142
[#permalink]
Show Tags
27 May 2017, 12:57
conneryeon001 wrote: Bunuel, Is there a reason why you skipped 5 among the possible values of x? It was a typo. Yes, c can be 5 too. Edited. Thank you for noticing.
_________________



Intern
Joined: 24 Jun 2016
Posts: 3
Location: United States (IL)

Re D0142
[#permalink]
Show Tags
06 Feb 2018, 14:03
I think this is a poorquality question and I agree with explanation.



Math Expert
Joined: 02 Sep 2009
Posts: 58434

Re: D0142
[#permalink]
Show Tags
06 Feb 2018, 20:44
shashant wrote: I think this is a poorquality question and I agree with explanation. Care to elaborate a bit? The question s 100% mathematically correct and GMATlike.
_________________



Intern
Joined: 19 Nov 2012
Posts: 26

Re: D0142
[#permalink]
Show Tags
25 Jun 2018, 08:49
This is a definitely a high quality question and I agree with the explanation.



Intern
Status: All our dreams can come true, if we have the courage to pursue them
Joined: 03 Jul 2015
Posts: 32
Location: India
Concentration: Technology, Finance
WE: Information Technology (Computer Software)

Re: D0142
[#permalink]
Show Tags
19 Sep 2018, 15:44
Very good, tricky and gmat kind of a question. Sad to see people are judging it as a poor quality question without properly understanding/thinking through the solution



Intern
Joined: 19 Apr 2016
Posts: 3

Re D0142
[#permalink]
Show Tags
26 Jan 2019, 11:43
I think this is a highquality question and I agree with explanation.







Go to page
1 2
Next
[ 22 posts ]



