December 15, 2018 December 15, 2018 10:00 PM PST 11:00 PM PST Get the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299) December 16, 2018 December 16, 2018 07:00 AM PST 09:00 AM PST Get personalized insights on how to achieve your Target Quant Score.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51218

What is the value of the twodigit number x?
[#permalink]
Show Tags
07 Oct 2015, 05:31
Question Stats:
66% (00:36) correct 34% (00:43) wrong based on 289 sessions
HideShow timer Statistics



CEO
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2711
Location: India
GMAT: INSIGHT
WE: Education (Education)

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
07 Oct 2015, 05:56
Bunuel wrote: What is the value of the twodigit number x?
(1) The sum of the two digits is 4. (2) The difference between the two digits is 2.
Kudos for a correct solution. Question : If x= ab where a and b are tens and units digit respectively then find x?Statement 1: a+b=4x may be 13 or 22 or 31. Hence, NOT SUFFICIENT Statement 2: ab = 2 or ba=2if ab=2 then x = 31 if ba=2 then x = 13. Hence, NOT SUFFICIENT Combining the two statementsx may still be 13 or 31 Hence, NOT SUFFICIENT Answer: option E
_________________
Prosper!!! GMATinsight Bhoopendra Singh and Dr.Sushma Jha email: info@GMATinsight.com I Call us : +919999687183 / 9891333772 Online OneonOne Skype based classes and Classroom Coaching in South and West Delhi http://www.GMATinsight.com/testimonials.html
ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION



Intern
Status: Focus  Determination  Domination
Joined: 02 Mar 2015
Posts: 37
Location: India

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
07 Oct 2015, 05:59
Bunuel wrote: What is the value of the twodigit number x?
(1) The sum of the two digits is 4. (2) The difference between the two digits is 2.
Kudos for a correct solution. statement 1: x can have following possible values 40 31 22 13 Insufficient statement 2: x can have following possible values 20 31 13 42 24 64 46 and so on Insufficient Combining statement 1 and statement 2 x can have values 31 and 13 Insufficient Answer :E 13
_________________
Let's Rock!



Manager
Joined: 21 Jun 2014
Posts: 131
Location: United States
Concentration: General Management, Strategy
GPA: 3.4
WE: Engineering (Computer Software)

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
07 Oct 2015, 09:46
Tens digit=x One's digit=y From A: \(x+y=4\) so number can be 13,31,22 A is not sufficient From B: \(xy=2\) so number can be 31 or \(yx=2\) so number can be 13 B is not sufficient Combining both of them together , number can be 13 or 31 E is the right answer.
_________________
Regards, Manish Khare "Every thing is fine at the end. If it is not fine ,then it is not the end "



Manager
Joined: 13 Mar 2013
Posts: 163
Location: United States
Concentration: Leadership, Technology
GPA: 3.5
WE: Engineering (Telecommunications)

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
07 Oct 2015, 17:59
What is the value of the twodigit number x? (1) The sum of the two digits is 4. (2) The difference between the two digits is 2. St 1  13,31 ,40 etc ... St 2  13,31 , 42, 24 , etc together 13, 31  hence e ans
_________________
Regards ,



Math Expert
Joined: 02 Sep 2009
Posts: 51218

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
11 Oct 2015, 06:16
Bunuel wrote: What is the value of the twodigit number x?
(1) The sum of the two digits is 4. (2) The difference between the two digits is 2.
Kudos for a correct solution. VERITAS PREP OFFICIAL SOLUTION:Question Type: What Is the Value? This question asks for the value of the twodigit number x. Given information in the question stem or diagram: x is a twodigit number. Statement 1: The sum of the two digits is 4. There are only four twodigit numbers that have digits that total 4. They are 13, 22, 31, and 40. Since that allows for more than one value for x, this statement is not sufficient. Eliminate choices A and D. Statement 2: The difference between the two digits is 2. This means that for the tens digit (T) and the units digit (U), either: T – U = 2, or U – T = 2. Many people confuse this statement and think that the tens digit must be larger, such as 64, where T – U = 2. However, 46 would also be acceptable since the difference between the digits is 2. Clearly this statement is not sufficient alone as there are many twodigit numbers where T – U = 2 or U – T = 2. Eliminate choice B. Together: When taking the statements together it is best to start with the more limiting statement. Statement 1 only allows four values: 13, 22, 31, and 40. How many of these values are compatible with Statement 2? Two of them: 31 is T – U = 2; and 13 is U – T = 2. They each have a difference of 2. Since there are still two possible values for the twodigit number x, the correct answer is E. Note: This is a classic C vs. E problem. Almost everyone gets it down to choice C or E, but many people forget to differentiate between 13 and 31. (They either miss one in their list of possibilities for the first statement or assume that it must be 31 for the reasons discussed above.) Remember to do your best to exhaust all possibilities before picking answer C.
_________________
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



Intern
Joined: 24 May 2015
Posts: 1

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
05 Feb 2016, 15:51
I totally follow how you get to (e). but dsn't "1 minus 3" = 2??? If the test meant for us to consider 13, would it not have stated "the difference between the two digits is 2"??? or am i overthinking.
Thanks



Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 6639
GPA: 3.82

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
06 Feb 2016, 18:36
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution. What is the value of the twodigit number x? (1) The sum of the two digits is 4. (2) The difference between the two digits is 2. In the original condition, it is twodigit integer, which makes 2 variables. You need 2 equations in order to match with the number of equations. For 1) 1 equation, for 2) 1 equation, which is likely to make C the answer. When 1) & 2), 13 and 31 are derived, which is not unique and not sufficient. Therefore, the answer is E. > For cases where we need 2 more equations, such as original conditions with “2 variables”, or “3 variables and 1 equation”, or “4 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 70% chance that C is the answer, while E has 25% chance. These two are the majority. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since C is most likely to be the answer using 1) and 2) separately according to DS definition (It saves us time). Obviously there may be cases where the answer is A, B, D or E.
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare The oneandonly World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy. "Only $99 for 3 month Online Course" "Free Resources30 day online access & Diagnostic Test" "Unlimited Access to over 120 free video lessons  try it yourself"



Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1137
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
28 Nov 2018, 07:12



Intern
Joined: 11 Oct 2017
Posts: 2

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
28 Nov 2018, 20:35
even i am confused. It says the difference is 2 and not 2. so 31 is the only number with +2 difference. where am i going wrong



Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1137
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
28 Nov 2018, 21:04



Intern
Joined: 11 Oct 2017
Posts: 2

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
28 Nov 2018, 21:11
thanks gmatbuster i got it now



Intern
Joined: 30 Oct 2018
Posts: 28

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
29 Nov 2018, 09:53
1) x+y =4 can be many options  1+3 , 3+1 , 2+2 2) xy = 2 again can be many options Combining on and two also will give us two options 13 or 31 hence E
_________________
 Plz Kudos! if my post helps....



Manager
Joined: 04 Oct 2017
Posts: 72

Re: What is the value of the twodigit number x?
[#permalink]
Show Tags
03 Dec 2018, 22:55
GMATinsight wrote: Bunuel wrote: What is the value of the twodigit number x?
(1) The sum of the two digits is 4. (2) The difference between the two digits is 2.
Kudos for a correct solution. Question : If x= ab where a and b are tens and units digit respectively then find x?Statement 1: a+b=4x may be 13 or 22 or 31. Hence, NOT SUFFICIENT Statement 2: ab = 2 or ba=2Hi, I choose C as I felt in 13, difference of the digits is 2. How to remove this ambiquity???? if ab=2 then x = 31 if ba=2 then x = 13. Hence, NOT SUFFICIENT Combining the two statementsx may still be 13 or 31 Hence, NOT SUFFICIENT Answer: option E




Re: What is the value of the twodigit number x? &nbs
[#permalink]
03 Dec 2018, 22:55






