GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 23 Sep 2018, 03:45

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

The palindrome 939 is the sum of three lesser palindromes. If the thre

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1088
The palindrome 939 is the sum of three lesser palindromes. If the thre  [#permalink]

Show Tags

New post 01 Sep 2018, 15:17
2
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

25% (02:15) correct 75% (01:51) wrong based on 24 sessions

HideShow timer Statistics

The palindrome 939 is the sum of three lesser palindromes. If the three have different lengths and use only the same two positive integers,
which is the sum of these two integers?

A. 8
B. 9
C. 10
D. 11
E. 12
Intern
Intern
avatar
Joined: 10 Jul 2018
Posts: 3
Location: India
Schools: ESMT
GMAT 1: 700 Q44 V44
GPA: 3.54
Re: The palindrome 939 is the sum of three lesser palindromes. If the thre  [#permalink]

Show Tags

New post 01 Sep 2018, 18:56
1
Answer: C

Eliminated choices which cannot be used in below structure to get 939 as described below:
8 - 1+7 / 2+6 / 3+5 /4+4
9 - 1+8 / 2+7 / 3+6 / 4+5
11 - 2+9 / 3+8 / 4+7 / 5+6
12 - 3+9 / 4+8 / 5+7 / 6+6
XYX
YY
X
However, 10 possible to be split into - 1+9 / 2+8 / 3+7 / 4+6 / 5+5 does have the combination of (1,9) which can fit into below structure and give us 939
919
11
9
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6800
The palindrome 939 is the sum of three lesser palindromes. If the thre  [#permalink]

Show Tags

New post 01 Sep 2018, 20:42
gracie wrote:
The palindrome 939 is the sum of three lesser palindromes. If the three have different lengths and use only the same two positive integers,
which is the sum of these two integers?

A. 8
B. 9
C. 10
D. 11
E. 12


firstly I take it that use only the same two positive integers, means use any one or both of same two positive integers

a logical and fast approach could be -

the SUM is 939 and the other two palindrome will sum up lesser than 100+10 that is <110
so the biggest palindrome is \(> 939-110\) or \(>829\) and therefore the hundreds digit will be 8 or 9

lets check with 8..
units digit of sum is 9, and that will be possible when two palindromes have 8 as units digit and third will become X9-2*8=X9-16=_3
so other digit will be 3
1) max possible sum = \(888+88+3 =979\neq{939}\)
2) other possibility = \(888+33+8 =929\neq{939}\)
so 8 is not the digit

Now let's check with 9..
units digit of sum is 9, and that will be possible when all three are ODD units digit or when two digits are even and the third is 9
But he biggest is 9X9, which is <939 so X<3, possible values 0, 1 and 2
a)when two palindromes have 0 as units digit and third will become 9.. but then we will not have 2-digit number
b) when two palindromes have 9 as units digit and third will become X9-2*9=X9-18=_1..
so other digit will be 1
possibility = \(919+11+9 =939=939\)
so the digits are 9 and 1, sum = 1+9=10

C
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

GMAT Club Bot
The palindrome 939 is the sum of three lesser palindromes. If the thre &nbs [#permalink] 01 Sep 2018, 20:42
Display posts from previous: Sort by

The palindrome 939 is the sum of three lesser palindromes. If the thre

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.