It is currently 17 Oct 2017, 17:32

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

D represents a single digit number from 1 to 9. What is the value of D

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 41873

Kudos [?]: 128603 [0], given: 12180

D represents a single digit number from 1 to 9. What is the value of D [#permalink]

Show Tags

New post 28 Jul 2017, 01:23
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

74% (01:17) correct 26% (01:49) wrong based on 78 sessions

HideShow timer Statistics

D represents a single digit number from 1 to 9. What is the value of D?

(1) D.D + DD = D.D × DD
(2) D is not a prime number.

The dot (.) represents a decimal point.
[Reveal] Spoiler: OA

_________________

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

Kudos [?]: 128603 [0], given: 12180

Director
Director
User avatar
G
Joined: 18 Aug 2016
Posts: 511

Kudos [?]: 139 [0], given: 123

GMAT 1: 630 Q47 V29
GMAT ToolKit User Premium Member Reviews Badge
Re: D represents a single digit number from 1 to 9. What is the value of D [#permalink]

Show Tags

New post 28 Jul 2017, 01:48
Bunuel wrote:
D represents a single digit number from 1 to 9. What is the value of D?

(1) D.D + DD = D.D × DD
(2) D is not a prime number.

The dot (.) represents a decimal point.


(1) D.D + DD = D.D × DD
1.1 + 11 = 1.1 * 11 Yes
2.2 + 22 = 2.2 * 22 No

9.9 + 99 = 9.9 * 99 No (Only D=1 can hold)

Sufficient

(2) D can represent 2, 3, 5, 7...Not Sufficient

A
_________________

We must try to achieve the best within us

Thanks
Luckisnoexcuse

Kudos [?]: 139 [0], given: 123

Intern
Intern
avatar
B
Joined: 21 Jun 2017
Posts: 10

Kudos [?]: 2 [0], given: 69

GMAT 1: 750 Q50 V41
Re: D represents a single digit number from 1 to 9. What is the value of D [#permalink]

Show Tags

New post 30 Jul 2017, 11:09
(1)Sufficient
D +D/10 + 11D = (D+D/10)*11D
-> 121D = 121D^2
-> D(D-1) = 0
D is from 1-9 so D =1
(2) Not
D can be 1,4,6,8,9

Kudos [?]: 2 [0], given: 69

Intern
Intern
avatar
B
Joined: 18 Aug 2017
Posts: 30

Kudos [?]: 9 [0], given: 17

GMAT 1: 670 Q49 V33
Re: D represents a single digit number from 1 to 9. What is the value of D [#permalink]

Show Tags

New post 24 Aug 2017, 01:15
My approach:

1- Let 2 digit number DD is a, then D.D = a/10

a/10 + a = a/10 x a
11a/10 = a^2 /10
11 = a (a is positive so we can get rid of a/10 on both side)

so D = 1 => SUFF

2- D not prime, so D can be 4, 6, 8 => INSUFF

A is the answer.

Kudos [?]: 9 [0], given: 17

Senior Manager
Senior Manager
avatar
B
Joined: 15 Jan 2017
Posts: 281

Kudos [?]: 21 [0], given: 622

Re: D represents a single digit number from 1 to 9. What is the value of D [#permalink]

Show Tags

New post 14 Sep 2017, 14:40
Tried plugging in, which worked:
1) 22*2.2 = 22+2.2 not possible
11*1.1 = 11+ 1.1 --> possible
Suff
2) D not prime -- multiple values possible then. Not suff

Ans A

Kudos [?]: 21 [0], given: 622

Re: D represents a single digit number from 1 to 9. What is the value of D   [#permalink] 14 Sep 2017, 14:40
Display posts from previous: Sort by

D represents a single digit number from 1 to 9. What is the value of D

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.