Author 
Message 
TAGS:

Hide Tags

Director
Status: Verbal Forum Moderator
Joined: 17 Apr 2013
Posts: 540
Location: India
GMAT 1: 710 Q50 V36 GMAT 2: 750 Q51 V41 GMAT 3: 790 Q51 V49
GPA: 3.3

If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
Updated on: 17 Jun 2014, 12:32
Question Stats:
60% (01:13) correct 40% (01:05) wrong based on 576 sessions
HideShow timer Statistics
If a and b are positive integers, what is the units digit of b ? (1) b is 25% greater than a. (2) If b is decreased by 50%, the result is not an integer.
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Like my post Send me a Kudos It is a Good manner. My Debrief: http://gmatclub.com/forum/howtoscore750and750imovedfrom710to189016.html
Originally posted by honchos on 17 Jun 2014, 12:28.
Last edited by Bunuel on 17 Jun 2014, 12:32, edited 1 time in total.
Edited the question




Math Expert
Joined: 02 Sep 2009
Posts: 47112

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
17 Jun 2014, 12:36




Intern
Joined: 26 Aug 2014
Posts: 1
Concentration: Operations, General Management
Schools: Kelley '18, McCombs '18, Scheller '18, Mays '18, Fisher '17, Krannert '18, Foster '18, Broad '18, Terry '18, UrbanaChampaign '18, W. P. Carey Arizona State '18, Smeal Penn'18

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
03 Aug 2015, 09:55
Hi Bunuel,
I think it should be A as the question stem states that a & b are positive integers, ruling out the possibility of b being 0.
Your comments please



Current Student
Joined: 20 Mar 2014
Posts: 2641
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
03 Aug 2015, 10:14
kakshay108@gmail.com wrote: Hi Bunuel,
I think it should be A as the question stem states that a & b are positive integers, ruling out the possibility of b being 0.
Your comments please Not really. Positive integers can also include numbers such as 10, 20, 35 , 77 or even 1000. Having a ,b POSITIVE INTEGERS only means that the selected integers are >0 NOT that their unit's digit is 0 (this may or may not be true as shown below). Per statement 1, b = 1.25 a This statement can not be sufficient as you do not know about a. Take 2 cases: a= 4, b = 5, units digit = 5 a =16, b = 20, unit's digit = 0 . Hence you get 2 different answers. Thus this statement is not sufficient.



Manager
Joined: 24 Nov 2013
Posts: 59

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
17 Sep 2015, 20:50
kakshay108@gmail.com wrote: Hi Bunuel,
I think it should be A as the question stem states that a & b are positive integers, ruling out the possibility of b being 0.
Your comments please Bunuel has mentioned that "the units digit of b could be 0"...he is not saying b is 0..Hope this clears your doubt.



Board of Directors
Joined: 17 Jul 2014
Posts: 2723
Location: United States (IL)
Concentration: Finance, Economics
GPA: 3.92
WE: General Management (Transportation)

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
14 Apr 2016, 18:24
honchos wrote: If a and b are positive integers, what is the units digit of b ? (1) b is 25% greater than a. (2) If b is decreased by 50%, the result is not an integer. 1. b=5a/4 so a must be a multiple of 4, and b a multiple of 5. a=4, b=5. a=8, b=10, 2 options, not sufficient. 2. b/2 = noninteger. so b is odd. 1+2. b is odd, and b is a multiple of 5. 5, 15, 25, 35, 45, etc. so always b has units digit 5.



Director
Joined: 13 Mar 2017
Posts: 610
Location: India
Concentration: General Management, Entrepreneurship
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
05 Oct 2017, 22:35
honchos wrote: If a and b are positive integers, what is the units digit of b ? (1) b is 25% greater than a. (2) If b is decreased by 50%, the result is not an integer. Given : positive integers a and b DS: units digit of b? Statement 1 : b = 1.25 a = (5/4)a So a is multiple of 4 and b is a multiple of 5 a= 4, b =5 a=8, b=10 a=12, b=15 a=16, b= 20 So, unit's digit of b is either 0 or 5 NOT SUFFICIENT Statement 2 : Lets say the resultant value is c. So c = 0.5b and c is not an integer. So, c must be an odd integer. Unit's digit can be 1,3,5,7,9 NOT SUFFICIENT Combined : Unit's digit = 5 SUFFICIENT
_________________
CAT 99th percentiler : VA 97.27  DILR 96.84  QA 98.04  OA 98.95 UPSC Aspirants : Get my app UPSC Important News Reader from Play store.
MBA Social Network : WebMaggu
Appreciate by Clicking +1 Kudos ( Lets be more generous friends.) What I believe is : "Nothing is Impossible, Even Impossible says I'm Possible" : "Stay Hungry, Stay Foolish".



Intern
Joined: 03 Dec 2016
Posts: 16
Location: United States
Concentration: Strategy, Finance
GPA: 3.97
WE: Business Development (Consulting)

Re: If a and b are positive integers, what is the units digit of
[#permalink]
Show Tags
09 Jan 2018, 08:54
shashankism wrote: honchos wrote: If a and b are positive integers, what is the units digit of b ? (1) b is 25% greater than a. (2) If b is decreased by 50%, the result is not an integer. Given : positive integers a and b DS: units digit of b? Statement 1 : b = 1.25 a = (5/4)a So a is multiple of 4 and b is a multiple of 5 a= 4, b =5 a=8, b=10 a=12, b=15 a=16, b= 20 So, unit's digit of b is either 0 or 5 NOT SUFFICIENT Statement 2 : Lets say the resultant value is c. So c = 0.5b and c is not an integer. So, c must be an odd integer. Unit's digit can be 1,3,5,7,9 NOT SUFFICIENT Combined : Unit's digit = 5 SUFFICIENTDo you mean that "b" must be an odd integer? Typo.




Re: If a and b are positive integers, what is the units digit of &nbs
[#permalink]
09 Jan 2018, 08:54






