Last visit was: 19 Jul 2024, 05:23 It is currently 19 Jul 2024, 05:23
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Tags:
Show Tags
Hide Tags
Math Expert
Joined: 02 Sep 2009
Posts: 94412
Own Kudos [?]: 642244 [31]
Given Kudos: 86292
Send PM
Most Helpful Reply
Senior Manager
Senior Manager
Joined: 02 Apr 2014
Posts: 369
Own Kudos [?]: 493 [9]
Given Kudos: 1227
Location: India
Schools: XLRI"20
GMAT 1: 700 Q50 V34
GPA: 3.5
Send PM
General Discussion
Director
Director
Joined: 05 Mar 2015
Posts: 840
Own Kudos [?]: 878 [0]
Given Kudos: 45
Send PM
Stacy Blackman Consulting Director of Test Prep
Joined: 21 Dec 2014
Affiliations: Stacy Blackman Consulting
Posts: 237
Own Kudos [?]: 398 [0]
Given Kudos: 165
Location: United States (DC)
GMAT 1: 790 Q51 V51
GRE 1: Q170 V170

GRE 2: Q170 V170
GPA: 3.11
WE:Education (Education)
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
rohit8865 wrote:
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10



(1) b^2=c

if b =-2 , c= 4
if b= -3 , c=9
a could be 5 or 6
not suff

(2)again same as (1)
insuff


combining same as above
insuff

Ans E


I believe that you are misinterpreting the question. a, b, and c represent digits, and ab, ba, and aca represent two two-digit numbers and a three-digit number. These are not products. Like, for instance, if a = 8 and b = 3, then ab would be 83, ba would be 38, etc.
Intern
Intern
Joined: 08 Jul 2013
Posts: 10
Own Kudos [?]: 23 [2]
Given Kudos: 38
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
2
Kudos
1.suff: 21 12 only combo acceptable as digits are different
2. insuff

answer A
Senior Manager
Senior Manager
Joined: 05 Jan 2017
Posts: 412
Own Kudos [?]: 285 [0]
Given Kudos: 15
Location: India
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


St 1: Nothing can be predicted. INSUFFICIENT

St 2: (a,b)/(b,a)can be (1,2)(1,3)(1,4).......(1,9), (2,3),(2,4). INSUFFICIENT

St 1 & St 2: for each possible set we will calculate ab*ba, that will be 252, 403, 574, 765,976....

only 12*21 = 252

hence ab can be 12 or 21. INSUFFICIENT

Option E
Intern
Intern
Joined: 08 Jul 2013
Posts: 10
Own Kudos [?]: 23 [1]
Given Kudos: 38
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
1
Kudos
ByjusGMATapp wrote:
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


St 1: Nothing can be predicted. INSUFFICIENT

St 2: (a,b)/(b,a)can be (1,2)(1,3)(1,4).......(1,9), (2,3),(2,4). INSUFFICIENT

St 1 & St 2: for each possible set we will calculate ab*ba, that will be 252, 403, 574, 765,976....

only 12*21 = 252

hence ab can be 12 or 21. INSUFFICIENT

Option E


ab can not be 12, only 21 because aca is 252
Intern
Intern
Joined: 25 Dec 2016
Posts: 14
Own Kudos [?]: 4 [0]
Given Kudos: 16
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
rt9 wrote:
ByjusGMATapp wrote:
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


St 1: Nothing can be predicted. INSUFFICIENT

St 2: (a,b)/(b,a)can be (1,2)(1,3)(1,4).......(1,9), (2,3),(2,4). INSUFFICIENT

St 1 & St 2: for each possible set we will calculate ab*ba, that will be 252, 403, 574, 765,976....

only 12*21 = 252

hence ab can be 12 or 21. INSUFFICIENT

Option E


ab can not be 12, only 21 because aca is 252


11 and 11 is another value
Math Expert
Joined: 02 Sep 2009
Posts: 94412
Own Kudos [?]: 642244 [0]
Given Kudos: 86292
Send PM
If a, b, and c represent distinct digits, what is the value of the two [#permalink]
Expert Reply
vivek2k70 wrote:
rt9 wrote:
ByjusGMATapp wrote:
St 1: Nothing can be predicted. INSUFFICIENT

St 2: (a,b)/(b,a)can be (1,2)(1,3)(1,4).......(1,9), (2,3),(2,4). INSUFFICIENT

St 1 & St 2: for each possible set we will calculate ab*ba, that will be 252, 403, 574, 765,976....

only 12*21 = 252

hence ab can be 12 or 21. INSUFFICIENT

Option E


ab can not be 12, only 21 because aca is 252


11 and 11 is another value


It is mentioned in the stem that a, b, and c represent distinct digits.
Manager
Manager
Joined: 03 Jul 2016
Status:Countdown Begins...
Posts: 242
Own Kudos [?]: 150 [4]
Given Kudos: 80
Location: India
Concentration: Technology, Strategy
Schools: IIMB
GMAT 1: 580 Q48 V22
GPA: 3.7
WE:Information Technology (Consulting)
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
4
Kudos
I am sure, you wanted to mention: If a, b, and C represent distinct digits
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


We know a,b,c are different digits.

ab*ba = aca

So from the 2 digit multiplication process, first we will multiply a*b. As we get the unit digit number as a itself, means b = 1.

just plugging the numbers 21 & 12 gives 252, means a=2, b=1, c=5.

Also there is no other integer which gives mutiplication X1 * 1X = X_X
A- sufficient.
Math Expert
Joined: 02 Sep 2009
Posts: 94412
Own Kudos [?]: 642244 [0]
Given Kudos: 86292
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
Expert Reply
RMD007 wrote:
I am sure, you wanted to mention: If a, b, and C represent distinct digits
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


We know a,b,c are different digits.

ab*ba = aca

So from the 2 digit multiplication process, first we will multiply a*b. As we get the unit digit number as a itself, means b = 1.

just plugging the numbers 21 & 12 gives 252, means a=2, b=1, c=5.

Also there is no other integer which gives mutiplication X1 * 1X = X_X
A- sufficient.


Sure. Edited. Thank you for noticing. +1.
Senior Manager
Senior Manager
Joined: 21 Mar 2016
Posts: 448
Own Kudos [?]: 120 [0]
Given Kudos: 103
Send PM
If a, b, and c represent distinct digits, what is the value of the two [#permalink]
ByjusGMATapp wrote:
Bunuel wrote:
If a, b, and b represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


St 1: Nothing can be predicted. INSUFFICIENT

St 2: (a,b)/(b,a)can be (1,2)(1,3)(1,4).......(1,9), (2,3),(2,4). INSUFFICIENT

St 1 & St 2: for each possible set we will calculate ab*ba, that will be 252, 403, 574, 765,976....

only 12*21 = 252

hence ab can be 12 or 21. INSUFFICIENT

Option E



ByjusGMATapp plz elaborate the stat1 ,, according to me stat 1 is suff and 12,21 is the only combo tat fits in.. thanks
Intern
Intern
Joined: 10 Dec 2019
Posts: 42
Own Kudos [?]: 6 [0]
Given Kudos: 15
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
Bunuel wrote:
If a, b, and c represent distinct digits, what is the value of the two-digit number ab?

(1) ab*ba = aca

(2) a*b < 10


Hi Bunuel

I believe for this, one has to remember or recognise multipliers of 21. Isn't there any simpler or easier method than that?

Please suggest. Thanks!
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 34019
Own Kudos [?]: 852 [0]
Given Kudos: 0
Send PM
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
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 Club Bot
Re: If a, b, and c represent distinct digits, what is the value of the two [#permalink]
Moderator:
Math Expert
94411 posts