January 17, 2019 January 17, 2019 08:00 AM PST 09:00 AM PST Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL. January 19, 2019 January 19, 2019 07:00 AM PST 09:00 AM PST Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 52231

What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
10 Dec 2018, 01:32
Question Stats:
33% (02:34) correct 67% (01:29) wrong based on 124 sessions
HideShow timer Statistics



VP
Joined: 18 Aug 2017
Posts: 1194
Location: India
Concentration: Sustainability, Marketing
WE: Marketing (Energy and Utilities)

Re: What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
11 Dec 2018, 01:29
Bunuel wrote: What is the value of a positive integer x?
(1) x is three times the sum of its digits (2) x is a twodigit number GMATinsight : Sir could you please review my solution and check where am I going wrong, correct answer given is A .. I am not sure why so.. we need to find the value of +ve integer X stmnt 1: X = 3* ( sum of its digits) its not clear how many digit number it is , if its 1 digit no then X= 3 .A if its a 2 digit no then X= 3*(10A+B) .. so on so value of X would vary as we are not sure of the value of 2 digits it can be (11,12 .. so on ) so x can be X= 3(2); 6 or 3(3); 9 or else it can be a 3 digit no as well eg 111 ; 3* (3); 9 100 : 3(1); 3 in sufficient Stmnt 2: X is a two digit no.. again value of 2 digit not clear so X cannot be determined , in sufficient From 1 & 2: x is a 2 digit no and it is 3 times the sum of the digits ; this would be again in sufficient as we would get many values of X as 2 digit no can be many IMO E should be answer..
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.



Manager
Joined: 18 Oct 2018
Posts: 51
Location: India
Concentration: Finance, International Business
GPA: 4
WE: Business Development (Retail Banking)

Re: What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
11 Dec 2018, 02:06
Answer is A. From stmnt 1,we know X=3*( sum of digits of X) Now,supposing X is A3 digit no.,999,sum of digits =27,and 3 times 27= 81,a 2 digit no.which is contradictory in itself. Considering X=100,sum of digits=1,hence 3 times 1=1,a one digit no. This means X should be a 2 digit no. Let X=10a+b Then 10a+b= 3*(a+b) Or 7a=2b,or a=3.5b. Now,for the 2 digit no.X,a and b should both be integers,and should be 0<a,b<=9. Only digits satisfying this are 2 and 7. So,X=27= 3*(2+7) Sufficient.
Stmnt 2 is insufficient
So,A
Posted from my mobile device



VP
Joined: 18 Aug 2017
Posts: 1194
Location: India
Concentration: Sustainability, Marketing
WE: Marketing (Energy and Utilities)

Re: What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
11 Dec 2018, 02:19
anshkool4u wrote: Answer is A. From stmnt 1,we know X=3*( sum of digits of X) Now,supposing X is A3 digit no.,999,sum of digits =27,and 3 times 27= 81,a 2 digit no.which is contradictory in itself. Considering X=100,sum of digits=1,hence 3 times 1=1,a one digit no. This means X should be a 2 digit no. Let X=10a+b Then 10a+b= 3*(a+b) Or 7a=2b,or a=3.5b. Now,for the 2 digit no.X,a and b should both be integers,and should be 0<a,b<=9. Only digits satisfying this are 2 and 7. So,X=27= 3*(2+7) Sufficient.
Stmnt 2 is insufficient
So,A
Posted from my mobile device anshkool4uquoting your line : Let X=10a+b Then 10a+b= 3*(a+b) Or 7a=2b,or a=3.5b.this would be 3.5a=b Now,for the 2 digit no.X ,a and b should both be integers,and should be 0<a,b<=9. " how did you come up to this range"? agree that a and b have to be between 09 but why specifically you have mentioned that "be 0<a,b<=9."
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.



Manager
Joined: 21 Jun 2017
Posts: 202
Concentration: Finance, Economics
WE: Corporate Finance (Commercial Banking)

Re: What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
23 Dec 2018, 23:42
Let X be of form pq . So basically X =10P + Q A> 3x = P + Q > 2Q = 7P For this to hold P should be 2 and Q should be 7 27 is the unique no. Sufficient B> No unique value. Insufficient Answer A Posted from my mobile device
_________________
Even if it takes me 30 attempts, I am determined enough to score 740+ in my 31st attempt. This is it, this is what I have been waiting for, now is the time to get up and fight, for my life is 100% my responsibility.
Dil ye Ziddi hai !!!



Math Expert
Joined: 02 Sep 2009
Posts: 52231

Re: What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
24 Dec 2018, 00:17



Manager
Joined: 18 Oct 2018
Posts: 51
Location: India
Concentration: Finance, International Business
GPA: 4
WE: Business Development (Retail Banking)

What is the value of a positive integer x? (1) x is three times the
[#permalink]
Show Tags
07 Jan 2019, 09:13
Archit3110 wrote: anshkool4u wrote: Answer is A. From stmnt 1,we know X=3*( sum of digits of X) Now,supposing X is A3 digit no.,999,sum of digits =27,and 3 times 27= 81,a 2 digit no.which is contradictory in itself. Considering X=100,sum of digits=1,hence 3 times 1=1,a one digit no. This means X should be a 2 digit no. Let X=10a+b Then 10a+b= 3*(a+b) Or 7a=2b,or a=3.5b. Now,for the 2 digit no.X,a and b should both be integers,and should be 0<a,b<=9. Only digits satisfying this are 2 and 7. So,X=27= 3*(2+7) Sufficient.
Stmnt 2 is insufficient
So,A
Posted from my mobile device anshkool4uquoting your line : Let X=10a+b Then 10a+b= 3*(a+b) Or 7a=2b,or a=3.5b.this would be 3.5a=b Now,for the 2 digit no.X ,a and b should both be integers,and should be 0<a,b<=9. " how did you come up to this range"? agree that a and b have to be between 09 but why specifically you have mentioned that "be 0<a,b<=9." Hi Archit, the range quoted is because if a=0, then the no. ab would just become a single digit no. and since 3.5a=b, value of b cannot be 0 because a cannot be 0. I hope that makes it clear.




What is the value of a positive integer x? (1) x is three times the &nbs
[#permalink]
07 Jan 2019, 09:13






