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

 It is currently 18 Oct 2019, 12:12

### 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

# which of the five numbers is multiplied by 3?

Author Message
TAGS:

### Hide Tags

VP
Joined: 31 Oct 2013
Posts: 1464
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 02:52
1
00:00

Difficulty:

45% (medium)

Question Stats:

73% (01:57) correct 27% (01:45) wrong based on 22 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: 313
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, 03:19
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: 7978
Re: which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 04:16
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
_________________
SVP
Joined: 26 Mar 2013
Posts: 2345
Re: which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 04:31
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: 4772
Location: India
GPA: 3.5
which of the five numbers is multiplied by 3?  [#permalink]

### Show Tags

24 Jan 2018, 06:39
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?   [#permalink] 24 Jan 2018, 06:39
Display posts from previous: Sort by