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

It is currently 23 Oct 2018, 05:43

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

If a and b represent positive single digits in the correctly worked co

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50058
If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 27 Oct 2014, 08:41
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

71% (01:07) correct 29% (01:11) wrong based on 310 sessions

HideShow timer Statistics

Tough and Tricky questions: Arithmetic.



22
a3
+4b
___
90

If a and b represent positive single digits in the correctly worked computation above, what is the value of the two digit integer ba?

A. 10
B. 15
C. 25
D. 51
E. 52

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
Status: Preparing
Joined: 09 Oct 2014
Posts: 12
Re: If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 27 Oct 2014, 08:52
I am such an idiot!
I got 25 for ab and obviously it was wrong and for next 3 minutes u was figuring out how the answer was 52!
then I re-read the question - ba.
*face-palm*
Manager
Manager
User avatar
Joined: 21 Jul 2014
Posts: 126
GMAT ToolKit User
Re: If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 27 Oct 2014, 09:03
1
Bunuel wrote:

Tough and Tricky questions: Arithmetic.



22
a3
+4b
___
90

If a and b represent positive single digits in the correctly worked computation above, what is the value of the two digit integer ba?

A. 10
B. 15
C. 25
D. 51
E. 52


Here is one way to solve this problem:
I switched the 4 in the tens digit with a so that i could turn it into a simple subtraction problem. I found it to be easier than solving each variable individually.
Image
Intern
Intern
avatar
B
Joined: 27 Oct 2014
Posts: 29
Premium Member
Re: If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 27 Oct 2014, 09:08
Let's tackle the units column first. 2+3+(some digit) has to give us a value that ends in 0. Only 5 works, so we can eliminate A, B, C. Now we can quickly test D and E. If we insert "2" for A, our equation becomes: 22+23+45, which equals 90. Hence, the answer is E.
SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1829
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 27 Oct 2014, 20:21
3
Bunuel wrote:

Tough and Tricky questions: Arithmetic.



22
a3
4b
___
90

If a and b represent positive single digits in the correctly worked computation above, what is the value of the two digit integer ba?

A. 10
B. 15
C. 25
D. 51
E. 52


"b" has to be "5" to give "0" at the end of the addition; so we can safely IGNORE option A, B & C

This takes a "carry 1" ahead in addition

1 + 2 + a + 4 = 9

a = 2

ba = 52

Answer = E
_________________

Kindly press "+1 Kudos" to appreciate :)

CEO
CEO
User avatar
D
Joined: 12 Sep 2015
Posts: 3031
Location: Canada
If a and b represent positive single digits in the correctly worked co  [#permalink]

Show Tags

New post 04 Aug 2018, 06:04
1
Top Contributor
Bunuel wrote:

Tough and Tricky questions: Arithmetic.



22
a3
+4b
___
90

If a and b represent positive single digits in the correctly worked computation above, what is the value of the two digit integer ba?

A. 10
B. 15
C. 25
D. 51
E. 52


Units digits first....
2 + 3 + b yields a sum with units digit 0
So, b = 5

So, the top number and bottom number are now 22 and 45
We have:
22
a3
+45
___
90

22 + 45 = 67
So, we have: 67 + a3 = 90
Subtract 67 from both sides to get: a3 = 23
So, a = 2

What is the value of the two digit integer ba?
ba = 52

Answer: E

Cheers,
Brent
_________________

Brent Hanneson – GMATPrepNow.com
Image
Sign up for our free Question of the Day emails

GMAT Club Bot
If a and b represent positive single digits in the correctly worked co &nbs [#permalink] 04 Aug 2018, 06:04
Display posts from previous: Sort by

If a and b represent positive single digits in the correctly worked co

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


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®.