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

 It is currently 20 Apr 2019, 19:26

### 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

# If the average (arithmetic mean) monthly sales of a department store w

Author Message
TAGS:

### Hide Tags

Manager
Joined: 02 Jun 2015
Posts: 190
Location: Ghana
If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

07 Jun 2017, 04:18
3
00:00

Difficulty:

75% (hard)

Question Stats:

47% (01:34) correct 53% (01:36) wrong based on 99 sessions

### HideShow timer Statistics

If the average (arithmetic mean) monthly sales of a department store was y dollars during a certain period of several years, what is the average biannual sales over the same period?

(1) The period includes exactly 4 years.
(2) y = 500.

_________________
Kindly press kudos if you find my post helpful
Director
Joined: 05 Mar 2015
Posts: 999
Re: If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

07 Jun 2017, 08:23
duahsolo wrote:
If the average (arithmetic mean) monthly sales of a department store was y dollars during a certain period of several years, what is the average biannual sales over the same period?

(1) The period includes exactly 4 years.
(2) y = 500.

total sales/ N (no. of months ) = y (given)

then total sales =???

(1) n= 48 (12*4=48)
not suff..

(2) y =500
n=2(biannual) *12 = 24

total sales = 500*24

suff

Ans B
Manager
Joined: 02 Feb 2016
Posts: 88
GMAT 1: 690 Q43 V41
Re: If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

05 Jul 2017, 13:58
rohit8865 wrote:
duahsolo wrote:
If the average (arithmetic mean) monthly sales of a department store was y dollars during a certain period of several years, what is the average biannual sales over the same period?

(1) The period includes exactly 4 years.
(2) y = 500.

total sales/ N (no. of months ) = y (given)

then total sales =???

(1) n= 48 (12*4=48)
not suff..

(2) y =500
n=2(biannual) *12 = 24

total sales = 500*24

suff

Ans B

How is 'n=2' multiplied by 12 in statement (2)?
Current Student
Joined: 28 Mar 2017
Posts: 30
Location: United Kingdom
GMAT 1: 710 Q48 V39
GPA: 2.7
If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

08 Jul 2017, 12:18
Given:
Total sales = s
Average monthly sales over x years = s/(12x) = y
Bi-annual means 2*x (in denominator). Therefore, question is asking what is s/(2x)?

1) x=4
s/(2*4)=s/8 --> not sufficient.

2) y=500
s/(12x) = 500
s = 6000x
s/(2x) = 6000x/2x = 3000. Hence sufficient.

Please correct me if I'm wrong.
Board of Directors
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3632
If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

09 Jul 2017, 00:54
1
rohit8865 wrote:
total sales/ N (no. of months ) = y (given)

then total sales =???

(1) n= 48 (12*4=48)
not suff..

(2) y =500
n=2(biannual) *12 = 24

total sales = 500*24

suff

Ans B

Hey rohit8865 ,

There is a problem in your solution. I have highlighted the same.

Total sale for x years = y * 12 * x

Biannual years means total years/2 = x/2

Average sale for biannual years = Total sale for x years/ number of biannual years = y *12 *x/2x = 6y.

Now, option B tells us the value of y, hence we can find out the average sale for biannual years. Hence, option B is sufficient.

TheMastermind wrote:
How is 'n=2' multiplied by 12 in statement (2)?

Hi TheMastermind ,

y is average monthly sale. Therefore to get annual sale, we are multiplying it with 12.

I hope that makes sense.
_________________
My GMAT Story: From V21 to V40
My MBA Journey: My 10 years long MBA Dream
My Secret Hacks: Best way to use GMATClub | Importance of an Error Log!
Verbal Resources: All SC Resources at one place | All CR Resources at one place

GMAT Club Inbuilt Error Log Functionality - View More.
New Visa Forum - Ask all your Visa Related Questions - here.
New! Best Reply Functionality on GMAT Club!
Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for free
Check our new About Us Page here.
Manager
Joined: 24 Jan 2017
Posts: 142
GMAT 1: 640 Q50 V25
GMAT 2: 710 Q50 V35
GPA: 3.48
If the average (arithmetic mean) monthly sales of a department store w  [#permalink]

### Show Tags

09 Jul 2017, 20:26
First, make sure what the question asks: what is the average biannual sales over the same period?

It means, let's figure out average sales in a 6-month basis over the same period: 6y.
Why? Let's call x: the number of years in that period --> Total sales in the period: 12xy
--> Average biannual sales: (12xy/2x) = 6y

Therefore, if we know value of y, surely we'll get the answer.

Now look at the statements

(1) The period includes exactly 4 years.
x=4. However, y is unknown. Depending on particular values of y, we will get different results of 6y

ELIMINATE (A) and (D)

(2) y = 500.
--> Average biannual sales: 6y = 6x500=3,000
Sufficient statement.

(B) IS CORRECT!
If the average (arithmetic mean) monthly sales of a department store w   [#permalink] 09 Jul 2017, 20:26
Display posts from previous: Sort by

# If the average (arithmetic mean) monthly sales of a department store w

 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®.