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

 It is currently 24 Jan 2019, 00:47

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### Key Strategies to Master GMAT SC

January 26, 2019

January 26, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.
• ### Free GMAT Number Properties Webinar

January 27, 2019

January 27, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn a structured approach to solve 700+ Number Properties question in less than 2 minutes.

# which of the five numbers is multiplied by 3?

Author Message
TAGS:

### Hide Tags

VP
Joined: 31 Oct 2013
Posts: 1014
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 01:52
1
00:00

Difficulty:

45% (medium)

Question Stats:

71% (01:58) correct 29% (01:45) wrong based on 21 sessions

### HideShow timer Statistics

The average of the five members is 7. if one of the members is multiplied by 3, the average of the numbers increases to 9.4. which of the five numbers is multiplied by 3?

a)4
b)5
c)5.6
d)6
e) none of these
Senior Manager
Joined: 17 Oct 2016
Posts: 318
Location: India
Concentration: Operations, Strategy
GPA: 3.73
WE: Design (Real Estate)
Re: which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 02:19
1
Let say the unknown digit be x and the sum of the remaining four digits be y.

Now (x+y)/5=7 ie y=35-x

Also (3x+y)/5=9.4 ie y=47-3x

Solving for x, the multiplied number is 6. Option D

Posted from my mobile device
_________________

Help with kudos if u found the post useful. Thanks

Math Expert
Joined: 02 Aug 2009
Posts: 7215
Re: which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 03:16
selim wrote:
The average of the five members is 7. if one of the members is multiplied by 3, the average of the numbers increases to 9.4. which of the five numbers is multiplied by 3?

a)4
b)5
c)5.6
d)6
e) none of these

hi

initial sum = 7*5=35
sum after a number is increased 3 times = 9.4*5=47
Increase = 47-35=12..

IMPORTANT point - number is multiplied by 3 MEANS number increases by 2 times..
so 2x=12...x=6

D
_________________

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

SVP
Joined: 26 Mar 2013
Posts: 2010
Re: which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 03:31
selim wrote:
The average of the five members is 7. if one of the members is multiplied by 3, the average of the numbers increases to 9.4. which of the five numbers is multiplied by 3?

a)4
b)5
c)5.6
d)6
e) none of these

Let the numbers a,b,c,d,e

a+b+c+d+e= 5 *7..........1

If a is multiplied by 3 (or any number)

3a+b+c+d+e= 5 *9.4 (do not bother multiply now).............2

Subtract 1 from 2

2a = 5 (9.4 -7) = 5 * 2.4).........divide by 2

a = 5 * 1.2 = 6

Tip: Sometimes it is easier not rush multiply numbers
Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4354
Location: India
GPA: 3.5
which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 05:39
selim wrote:
The average of the five members is 7. if one of the members is multiplied by 3, the average of the numbers increases to 9.4. which of the five numbers is multiplied by 3?

a)4
b)5
c)5.6
d)6
e) none of these

$$a + b + c + d + e = 35$$--------------------->(I)
$$3a + b + c + d + e = 47$$------------------->(II)

$$(II) - (I)$$ : $$2a = 12$$ , $$a = 6$$, Answer must be (D)
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

which of the five numbers is multiplied by 3? &nbs [#permalink] 24 Jan 2018, 05:39
Display posts from previous: Sort by