December 11, 2018 December 11, 2018 09:00 PM EST 10:00 PM EST Strategies and techniques for approaching featured GMAT topics. December 11 at 9 PM EST. December 13, 2018 December 13, 2018 08:00 AM PST 09:00 AM PST What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51097

What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Apr 2012, 00:51
Question Stats:
63% (00:50) correct 37% (00:44) wrong based on 508 sessions
HideShow timer Statistics



Manager
Status: struggling with GMAT
Joined: 06 Dec 2012
Posts: 133
Location: Bangladesh
Concentration: Accounting
GMAT Date: 04062013
GPA: 3.65

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
27 Mar 2013, 01:10
What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0



Verbal Forum Moderator
Joined: 10 Oct 2012
Posts: 611

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
27 Mar 2013, 01:45
mun23 wrote: What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0 From F.S 1, let's pick values keeping a – b = 6. For a=12; b=6, we have ab = 18, however, for a=12;b=6 we have ab = 6. Insufficient. From F.S 2, we just know that a and b are of the same sign. Insufficient. With both taken together, either a,b>0 in which case, a – b = 6 > a– b = 6 . or a,b<0 in which case, ba = 6. Thus, the distance between the points a and b, ab is the same in either case. Sufficient. C.
_________________
All that is equal and notDeep Dive Inequality
Hit and Trial for Integral Solutions



Math Expert
Joined: 02 Sep 2009
Posts: 51097

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
27 Mar 2013, 03:25



Senior Manager
Joined: 13 May 2013
Posts: 425

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
26 Jun 2013, 13:42
What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0
(1) a – b = 6
I made a stupid mistake here. I assumed that because we are dealing with absolute values here, we're dealing with just a positive number  a positive number (for example 126 = 6, 82 = 6, etc). Of course, we're looking for the distance of a and b, not the difference between a and b. For example, the difference between 12 and 6 is (126=6) but on the number line they are actually 18 places apart. Therefore, we cannot determine what the distance between a and b is on the number line with #1. INSUFFICIENT
(2) ab > 0
This tells us nothing about the placement of a and b on the number line, only that a and b are both positive or negative.
1+2) If a and b are both positive or both negative and that a – b = 6 then we can conclude the distance is always going to be 6. SUFFICIENT
(C)



Math Expert
Joined: 02 Sep 2009
Posts: 51097

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
23 Nov 2014, 04:34



Director
Status: Come! Fall in Love with Learning!
Joined: 05 Jan 2017
Posts: 505
Location: India

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
15 Mar 2017, 01:03
Bunuel wrote: What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0 ST 1: If both are negative or both are positive, the difference will be = 6. If one of them is negative, we cannot determine the distance. INSUFFICIENT St 2: ab>0, that means either both are negative or both are positive. But the difference is unknown. INSUFFICIENT St 1 & St 2: the case of one of them being negative and other positive is ruled out. hence the distance will be 6. ANSWER Option C
_________________
GMAT Mentors



Manager
Joined: 27 Aug 2016
Posts: 89
Location: India
GPA: 3
WE: Engineering (Energy and Utilities)

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
31 May 2017, 22:05
Bunuel wrote: Bunuel wrote: What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0 What is the distance between a and b on the number line? We are asked to find the value of ab. (1) a – b = 6 > if a=7 and b=1 then ab=6 but if a=7 and b=1 then ab=8. Not sufficient. (2) ab > 0 > just says that a and b have the same sign. Not sufficient: (1)+(2) If both a and b are positive then ab=ab=6 and ab=6. If both a and b are negative then ab=a(b)=ba=6, and ab=6. So, in any case ab=6. Sufficient. Answer: C. Hello Bunuel, Your solution is well taken. However, I have been handling mod questions on the basis of "Distance from zero on number line" concept. Can we cay that mod (a) denotes the distnace of "a" from zero? If we can then option a states that the difference of "distance of a from zero" and "difference of b from" zero is equal to 6. the distance between "a" and "b" is 6 only. As only distance is required not the actual value. so whatever be the case, the distance of a and b will be 6 only. taking an example, let the value of "a" be 67 i.e. "a" is at a distance of 67 units from zero n the number line, therefore as per the given statement (i) b can take values of 61 and 73, thereby giving two differnt values. hence SUFFICIENT. From statement (ii) we see that either both a & b are positive or negative. Clearly INSUFFICIENT. So, option A should be the answer, What am I doing wrong here?? My concept is at stake



Math Expert
Joined: 02 Sep 2009
Posts: 51097

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
31 May 2017, 22:18
saurabhsavant wrote: Bunuel wrote: Bunuel wrote: What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0 What is the distance between a and b on the number line? We are asked to find the value of ab. (1) a – b = 6 > if a=7 and b=1 then ab=6 but if a=7 and b=1 then ab=8. Not sufficient. (2) ab > 0 > just says that a and b have the same sign. Not sufficient: (1)+(2) If both a and b are positive then ab=ab=6 and ab=6. If both a and b are negative then ab=a(b)=ba=6, and ab=6. So, in any case ab=6. Sufficient. Answer: C. Hello Bunuel, Your solution is well taken. However, I have been handling mod questions on the basis of "Distance from zero on number line" concept. Can we cay that mod (a) denotes the distnace of "a" from zero? If we can then option a states that the difference of "distance of a from zero" and "difference of b from" zero is equal to 6. the distance between "a" and "b" is 6 only. As only distance is required not the actual value. so whatever be the case, the distance of a and b will be 6 only. taking an example, let the value of "a" be 67 i.e. "a" is at a distance of 67 units from zero n the number line, therefore as per the given statement (i) b can take values of 61 and 73, thereby giving two differnt values. hence SUFFICIENT. From statement (ii) we see that either both a & b are positive or negative. Clearly INSUFFICIENT. So, option A should be the answer, What am I doing wrong here?? My concept is at stake How is your examples correct? If a = 67 and b =73, then a – b = 6, not 6. a – b = 6 (a = 6 + b) means that a is 6 units further from 0, than b is. You are considering the case when both a and b are negative. In my solution you can see an examples giving different answers: a=7 and b=1 then ab=6 a=7 and b=1 then ab=8.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 27 Aug 2016
Posts: 89
Location: India
GPA: 3
WE: Engineering (Energy and Utilities)

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 10:41
Bunuel wrote: saurabhsavant wrote: Bunuel wrote: [quote="Bunuel"]What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0 What is the distance between a and b on the number line? We are asked to find the value of ab. (1) a – b = 6 > if a=7 and b=1 then ab=6 but if a=7 and b=1 then ab=8. Not sufficient. (2) ab > 0 > just says that a and b have the same sign. Not sufficient: (1)+(2) If both a and b are positive then ab=ab=6 and ab=6. If both a and b are negative then ab=a(b)=ba=6, and ab=6. So, in any case ab=6. Sufficient. Answer: C. Hello Bunuel, Your solution is well taken. However, I have been handling mod questions on the basis of "Distance from zero on number line" concept. Can we cay that mod (a) denotes the distnace of "a" from zero? If we can then option a states that the difference of "distance of a from zero" and "difference of b from" zero is equal to 6. the distance between "a" and "b" is 6 only. As only distance is required not the actual value. so whatever be the case, the distance of a and b will be 6 only. taking an example, let the value of "a" be 67 i.e. "a" is at a distance of 67 units from zero n the number line, therefore as per the given statement (i) b can take values of 61 and 73, thereby giving two differnt values. hence SUFFICIENT. From statement (ii) we see that either both a & b are positive or negative. Clearly INSUFFICIENT. So, option A should be the answer, What am I doing wrong here?? My concept is at stake How is your examples correct? If a = 67 and b =73, then a – b = 6, not 6. a – b = 6 (a = 6 + b) means that a is 6 units further from 0, than b is. You are considering the case when both a and b are negative. In my solution you can see an examples giving different answers: a=7 and b=1 then ab=6 a=7 and b=1 then ab=8.[/quote] Agreed that i botched up in calculations...have been struggling with this issue....but even if we get negative 6 as an answer still the "distance" between a and b remains 6. Sent from my MI MAX using GMAT Club Forum mobile app



Math Expert
Joined: 02 Sep 2009
Posts: 51097

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 10:45



Manager
Joined: 27 Aug 2016
Posts: 89
Location: India
GPA: 3
WE: Engineering (Energy and Utilities)

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 11:22
Bunuel wrote: saurabhsavant wrote: Agreed that i botched up in calculations...have been struggling with this issue....but even if we get negative 6 as an answer still the "distance" between a and b remains 6. Sent from my MI MAX using GMAT Club Forum mobile appI don't understand what you are trying to say. What is your question exactly? Sorry to bother u..i really mean it...but here is what i gather from the question.. Ial = distance of a from zero..hope this concept is right? And ditto for b So i guess distance between a and b would not b lab...rather  ab ... Further, if a is say 100 units from zero, then a can be at either positive 100 or negative 100. Now, how do we placee b? We can place b in such a manner that statement i holds good. I.e. b =6+wherever a is....or gap between a and b is 6. Sent from my MI MAX using GMAT Club Forum mobile app



Manager
Joined: 27 Aug 2016
Posts: 89
Location: India
GPA: 3
WE: Engineering (Energy and Utilities)

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 11:27
saurabhsavant wrote: Bunuel wrote: saurabhsavant wrote: Agreed that i botched up in calculations...have been struggling with this issue....but even if we get negative 6 as an answer still the "distance" between a and b remains 6. Sent from my MI MAX using GMAT Club Forum mobile appI don't understand what you are trying to say. What is your question exactly? Sorry to bother u..i really mean it...but here is what i gather from the question.. Ial = distance of a from zero..hope this concept is right? And ditto for b So i guess distance between a and b would not b lab...rather  ab ... Further, if a is say 100 units from zero, then a can be at either positive 100 or negative 100. Now, how do we placee b? We can place b in such a manner that statement i holds good. I.e. b =6+wherever a is....or gap between a and b is 6. Sent from my MI MAX using GMAT Club Forum mobile appOne addition..b = wherever a is minus 6...again gap is 6 Sent from my MI MAX using GMAT Club Forum mobile app



Math Expert
Joined: 02 Sep 2009
Posts: 51097

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 11:28
saurabhsavant wrote: Bunuel wrote: saurabhsavant wrote: Agreed that i botched up in calculations...have been struggling with this issue....but even if we get negative 6 as an answer still the "distance" between a and b remains 6. Sent from my MI MAX using GMAT Club Forum mobile appI don't understand what you are trying to say. What is your question exactly? Sorry to bother u..i really mean it...but here is what i gather from the question.. Ial = distance of a from zero..hope this concept is right? And ditto for b So i guess distance between a and b would not b lab...rather  ab ...Further, if a is say 100 units from zero, then a can be at either positive 100 or negative 100. Now, how do we placee b? We can place b in such a manner that statement i holds good. I.e. b =6+wherever a is....or gap between a and b is 6. Sent from my MI MAX using GMAT Club Forum mobile appThe red part is where you are making an error. The distance between a and b on the number line mean a  b, and no way a  b.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 27 Aug 2016
Posts: 89
Location: India
GPA: 3
WE: Engineering (Energy and Utilities)

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
01 Jun 2017, 11:33
Bunuel wrote: saurabhsavant wrote: Bunuel wrote: [quote="saurabhsavant"] Agreed that i botched up in calculations...have been struggling with this issue....but even if we get negative 6 as an answer still the "distance" between a and b remains 6. Sent from my MI MAX using GMAT Club Forum mobile appI don't understand what you are trying to say. What is your question exactly? Sorry to bother u..i really mean it...but here is what i gather from the question.. Ial = distance of a from zero..hope this concept is right? And ditto for b So i guess distance between a and b would not b lab...rather  ab ...Further, if a is say 100 units from zero, then a can be at either positive 100 or negative 100. Now, how do we placee b? We can place b in such a manner that statement i holds good. I.e. b =6+wherever a is....or gap between a and b is 6. Sent from my MI MAX using GMAT Club Forum mobile appThe red part is where you are making an error. The distance between a and b on the number line mean a  b, and no way a  b.[/quote] Well...thanx for the help...will ponder over it and hope to reconcile with the OA. Sent from my MI MAX using GMAT Club Forum mobile app



Senior Manager
Joined: 15 Jan 2017
Posts: 356

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
15 Jul 2017, 06:14
WholeLottaLove wrote: What is the distance between a and b on the number line?
(1) a – b = 6 (2) ab > 0
(1) a – b = 6
I made a stupid mistake here. I assumed that because we are dealing with absolute values here, we're dealing with just a positive number  a positive number (for example 126 = 6, 82 = 6, etc). Of course, we're looking for the distance of a and b, not the difference between a and b. For example, the difference between 12 and 6 is (126=6) but on the number line they are actually 18 places apart. Therefore, we cannot determine what the distance between a and b is on the number line with #1. INSUFFICIENT
(2) ab > 0
This tells us nothing about the placement of a and b on the number line, only that a and b are both positive or negative.
1+2) If a and b are both positive or both negative and that a – b = 6 then we can conclude the distance is always going to be 6. SUFFICIENT
(C) Made the same error : now realize its asking DISTANCE not direction. So that remains the same through C. Picked E earlier as I kept thinking what is A and B Good one, conceptually Thank you for the explanation!



NonHuman User
Joined: 09 Sep 2013
Posts: 9105

Re: What is the distance between a and b on the number line?
[#permalink]
Show Tags
23 Nov 2018, 01:18
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 Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: What is the distance between a and b on the number line? &nbs
[#permalink]
23 Nov 2018, 01:18






