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

 It is currently 18 Aug 2018, 23:14

### 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

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

# D01-11

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 47983

### Show Tags

16 Sep 2014, 00:11
1
00:00

Difficulty:

25% (medium)

Question Stats:

74% (01:18) correct 26% (01:19) wrong based on 154 sessions

### HideShow timer Statistics

If $$S$$ is the sum of the digits of a given number, $$T$$ is the sum of the digit of $$S$$, and $$G$$ is the sum of digits in $$T$$. For example $$S$$ of 987 is $$9+8+7 = 24$$, $$T$$ of $$S$$ is $$2+4 = 6$$ and $$G$$ of 6 is 6. Therefore $$G$$ of 987 is 6. Which of the following has the greatest $$G$$?

A. 94123
B. 91964
C. 64678
D. 62355
E. 45689

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 47983

### Show Tags

16 Sep 2014, 00:11
Official Solution:

If $$S$$ is the sum of the digits of a given number, $$T$$ is the sum of the digit of $$S$$, and $$G$$ is the sum of digits in $$T$$. For example $$S$$ of 987 is $$9+8+7 = 24$$, $$T$$ of $$S$$ is $$2+4 = 6$$ and $$G$$ of 6 is 6. Therefore $$G$$ of 987 is 6. Which of the following has the greatest $$G$$?

A. 94123
B. 91964
C. 64678
D. 62355
E. 45689

The explanation follows as under: $$G$$ of 45689 is 5 whereas the rest have $$G$$ smaller than 5.

A. $$S = 9+4+1+2+3 = 19$$, $$T = 1+9 = 10$$ and $$G = 1+0 = 1$$.

B. $$S = 29$$, $$T = 11$$ and $$G = 2$$.

C. $$S = 31$$, $$T = 4$$, and $$G = 4$$.

D. $$S = 21$$, $$T = 3$$, and $$G = 3$$.

E. $$S = 32$$, $$T = 5$$, and $$G = 5$$.

Therefore E is the highest.

_________________
Intern
Joined: 13 Sep 2013
Posts: 1

### Show Tags

04 Dec 2014, 11:05
Is there a shortcut to do this? It's not hard to add up all the options manually..
Senior Manager
Joined: 25 Mar 2013
Posts: 263
Location: United States
Concentration: Entrepreneurship, Marketing
GPA: 3.5

### Show Tags

05 Dec 2014, 06:41
E
But took 2.15sec
Solved by adding each Digits in mind and noted down
Finding Out just S is Enough
Greater S value >>Mean Greater T >> Greater G!

_________________

I welcome analysis on my posts and kudo +1 if helpful. It helps me to improve my craft.Thank you

Intern
Joined: 09 Mar 2013
Posts: 18
Location: Russian Federation
Concentration: General Management, Entrepreneurship
GMAT 1: 550 Q43 V23
GMAT 2: 590 Q49 V22
GMAT 3: 690 Q49 V34
GMAT 4: 740 Q49 V41

### Show Tags

05 Dec 2014, 15:56
kanusha wrote:
E
Greater S value >>Mean Greater T >> Greater G!

it doesn't work
look
S in B) is greater than S in D), however T is greater in D) than in B)
Intern
Joined: 12 Mar 2015
Posts: 46
Schools: Haas '20
GPA: 2.99
WE: Corporate Finance (Aerospace and Defense)

### Show Tags

20 Feb 2016, 14:39
this requires just the ability to process basic arithmetic quickly in your head.
Intern
Joined: 26 Jul 2016
Posts: 28
Location: India
Concentration: Operations, Entrepreneurship
Schools: Tepper '19
GPA: 3.69
WE: Analyst (Manufacturing)

### Show Tags

05 Oct 2016, 05:50
another way is to cancel out the number in your head first cut 9 then 5 etc.. then u will be left with e last value with maximum weightage
Senior Manager
Joined: 18 Jun 2016
Posts: 269
Location: India
GMAT 1: 720 Q50 V38
GMAT 2: 750 Q49 V42
GPA: 4
WE: General Management (Other)

### Show Tags

16 Jul 2017, 12:28
I think this is a poor-quality question and I agree with explanation. Because there is no shorter way to solve this question.
_________________

I'd appreciate learning about the grammatical errors in my posts

Please hit Kudos If my Solution helps

My Debrief for 750 - https://gmatclub.com/forum/from-720-to-750-one-of-the-most-difficult-pleatues-to-overcome-246420.html

My CR notes - https://gmatclub.com/forum/patterns-in-cr-questions-243450.html

Manager
Joined: 02 Nov 2015
Posts: 169
GMAT 1: 640 Q49 V29

### Show Tags

18 Jul 2017, 09:53
seeing the question stem I understand that its simply adding the individual digits of each number. so option E yields 32 which is the highest.
Intern
Joined: 21 May 2015
Posts: 17

### Show Tags

21 Aug 2017, 15:28
rayzha wrote:
Is there a shortcut to do this? It's not hard to add up all the options manually..

Yes, these type of problems are called digit sum. The shortest way is to find out the remainder when divided by 9.

Cheers!
Manager
Joined: 12 Jun 2016
Posts: 219
Location: India
WE: Sales (Telecommunications)

### Show Tags

16 Oct 2017, 03:49
1
Hello umg,

I too had the same concern. I did some digging on this and found some interesting properties. You too may find them useful.

Sum of individual sums of a number is called Digit sum or Beejank (in Vedic maths). One shortcut to quickly arrive at the digit sum is to simply ignore 9's. Let me take the first option - 94123. The Digit sum is - 9 + 4 + 1 + 2 + 3 = 1 (Simply strike out the digit 9 or the numbers that add up to 9. You can try it on others options and find that this holds true.

While I was at it, I also discovered that digit-sum/Beejank can be used to quickly check if the addition/multiplications done are correct. There are a lot of links that explain this approach. One such link is - http://www.quickermaths.com/checking-of ... out-nines/

umg wrote:
I think this is a poor-quality question and I agree with explanation. Because there is no shorter way to solve this question.

_________________

My Best is yet to come!

Manager
Joined: 15 Sep 2016
Posts: 74
Location: Pakistan
Concentration: Finance, Technology
Schools: CBS '20
GMAT 1: 640 Q43 V35

### Show Tags

25 Nov 2017, 23:04
I solved the question using simple addition. I don't know the probability of this question showing up on the GMAT exam. but thanks to susheelh and his method:

susheelh wrote:

While I was at it, I also discovered that digit-sum/Beejank can be used to quickly check if the addition/multiplications done are correct. There are a lot of links that explain this approach. One such link is - http://www.quickermaths.com/checking-of ... -out-nines

I could solve the question in a minute or a few seconds less.
_________________

If you must err, err on the side of hope.

D01-11 &nbs [#permalink] 25 Nov 2017, 23:04
Display posts from previous: Sort by

# D01-11

Moderators: chetan2u, Bunuel

# Events & Promotions

 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®.