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

It is currently 18 Oct 2019, 16:40

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

Let a and b be digits. What is the sum b.aaa + a.bbb?

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58453
Let a and b be digits. What is the sum b.aaa + a.bbb?  [#permalink]

Show Tags

New post 10 Jan 2017, 04:03
1
4
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

59% (01:19) correct 41% (01:09) wrong based on 145 sessions

HideShow timer Statistics

Most Helpful Community Reply
Senior Manager
Senior Manager
avatar
B
Joined: 13 Oct 2016
Posts: 359
GPA: 3.98
Re: Let a and b be digits. What is the sum b.aaa + a.bbb?  [#permalink]

Show Tags

New post 10 Jan 2017, 06:34
2
3
Bunuel wrote:
Let a and b be digits. What is the sum b.aaa + a.bbb?

(1) a + b = 10
(2) a = b


\(b.aaa + a.bbb = \frac{baaa}{1000} + \frac{abbb}{1000} = \frac{1000b + 100a + 10 a + a + 1000a + 100b + 10b + b}{1000} =

= a+b + \frac{a + b}{10} + \frac{a + b}{100} + \frac{a + b}{1000}\)

(1) a + b = 10

10 + 1 + 0.1 + 0.01 = 11.11 Sufficient.

(2) a = b

\(2a + \frac{2a}{10} + \frac{2a}{100} + \frac{2a}{1000}\). No information about a or b (1.111 + 1.111 or 2.222 + 2.222 etc.). Insufficient.

Answer A
General Discussion
SVP
SVP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1684
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
Reviews Badge CAT Tests
Re: Let a and b be digits. What is the sum b.aaa + a.bbb?  [#permalink]

Show Tags

New post 11 Jan 2017, 00:20
1
Bunuel wrote:
Let a and b be digits. What is the sum b.aaa + a.bbb?

(1) a + b = 10
(2) a = b


Digits are from 0 to 9.

As per statement 1:

a + b = 10

various combinations are 1+9, 2+8, 3+6 etc.
So if a = 1 and b = 9 we have 1.999 + 9.111 = 11.11
a = 2 and b = 8 we have 2.888 + 8.222 = 11.11 etc (various combinations gives the same value . Sufficient

As per statement 2:

a = b

There may various combinations that will yield different sums of a & b
1.111 + 1.111 = 2.222
2.222 + 2.222 = 4.444

Not Sufficient.

(A)
_________________
"Do not watch clock; Do what it does. KEEP GOING."
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13262
Re: Let a and b be digits. What is the sum b.aaa + a.bbb?  [#permalink]

Show Tags

New post 06 May 2019, 06:35
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: Let a and b be digits. What is the sum b.aaa + a.bbb?   [#permalink] 06 May 2019, 06:35
Display posts from previous: Sort by

Let a and b be digits. What is the sum b.aaa + a.bbb?

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





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