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

 It is currently 18 Apr 2019, 05:35

### 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

# Set A contains 120 terms with an average of 8.2. Set B contains 240

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

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 54367
Set A contains 120 terms with an average of 8.2. Set B contains 240  [#permalink]

### Show Tags

28 Jul 2017, 09:08
1
00:00

Difficulty:

15% (low)

Question Stats:

89% (01:57) correct 11% (02:11) wrong based on 72 sessions

### HideShow timer Statistics

Set A contains 120 terms with an average of 8.2. Set B contains 240 terms with an average of 10.6. If Set A and B are combined what is the resulting average?

(A) 8.4

(B) 8.8

(C) 9.0

(D) 9.8

(E) 10.1

_________________
Verbal Forum Moderator
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 2246
Location: India
Concentration: General Management, Strategy
Schools: Kelley '20, ISB '19
GPA: 3.2
WE: Information Technology (Consulting)
Re: Set A contains 120 terms with an average of 8.2. Set B contains 240  [#permalink]

### Show Tags

28 Jul 2017, 10:17
2
1
Bunuel wrote:
Set A contains 120 terms with an average of 8.2. Set B contains 240 terms with an average of 10.6. If Set A and B are combined what is the resulting average?

(A) 8.4

(B) 8.8

(C) 9.0

(D) 9.8

(E) 10.1

Weighted average = (120*8.2 + 240*10.6) / 120 +240
=984+ 2544 / 360
=3528/360 = 9.8

The above method is calculation intensive.
Alternatively ,
Set A has 120 terms with average 8.2
Set B has 240 terms with average 10.6

Difference between average of set A and B = 2.4
Number of terms of B : Number of terms of A = 2:1
2x+x = 2.4
=> x = .8
So the weighted average will be in opposite ratio of relative weights
8.2+ 2*.8 = 9.8

_________________
When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful
Director
Joined: 13 Mar 2017
Posts: 718
Location: India
Concentration: General Management, Entrepreneurship
GPA: 3.8
WE: Engineering (Energy and Utilities)
Re: Set A contains 120 terms with an average of 8.2. Set B contains 240  [#permalink]

### Show Tags

28 Jul 2017, 11:00
Bunuel wrote:
Set A contains 120 terms with an average of 8.2. Set B contains 240 terms with an average of 10.6. If Set A and B are combined what is the resulting average?

(A) 8.4

(B) 8.8

(C) 9.0

(D) 9.8

(E) 10.1

Avg. A = 8.2
n (A) = 120
Total A = 120 * 8.2 = 12 * 82 = 984

Avg. B = 10.6
n (B) = 240
Total B = 240 * 10.6 = 24 * 106 = 2544

Resulting average = (12* 82 + 24 * 106 ) /(120 +240) = (12* 82 + 24 * 106 ) /(360) = (82 +212)/30 = 294/30 = 98/10 = 9.8

_________________
CAT 2017 (98.95) & 2018 (98.91) : 99th percentiler
UPSC Aspirants : Get my app UPSC Important News Reader from Play store.

MBA Social Network : WebMaggu

Appreciate by Clicking +1 Kudos ( Lets be more generous friends.)

What I believe is : "Nothing is Impossible, Even Impossible says I'm Possible" : "Stay Hungry, Stay Foolish".
Current Student
Joined: 18 Aug 2016
Posts: 619
Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29
GMAT 2: 740 Q51 V38
Re: Set A contains 120 terms with an average of 8.2. Set B contains 240  [#permalink]

### Show Tags

30 Jul 2017, 00:17
2
Bunuel wrote:
Set A contains 120 terms with an average of 8.2. Set B contains 240 terms with an average of 10.6. If Set A and B are combined what is the resulting average?

(A) 8.4

(B) 8.8

(C) 9.0

(D) 9.8

(E) 10.1

Total terms in set B is 240 and set A is 120
Now Average will be more towards 10.6

8.2................10.6
Difference is 2.4 divide it into 3 parts (2:1) = 0.8
10.6-0.8 = 9.8

D
_________________
We must try to achieve the best within us

Thanks
Luckisnoexcuse
Senior SC Moderator
Joined: 22 May 2016
Posts: 2632
Set A contains 120 terms with an average of 8.2. Set B contains 240  [#permalink]

### Show Tags

31 Jul 2017, 07:47
1
Bunuel wrote:
Set A contains 120 terms with an average of 8.2. Set B contains 240 terms with an average of 10.6. If Set A and B are combined what is the resulting average?

(A) 8.4

(B) 8.8

(C) 9.0

(D) 9.8

(E) 10.1

I used neither alligation nor difference between averages, but I simplified the arithmetic.

Number of terms determines the weight of each value.

120 terms and 240 terms have the same weight as 1 term and 2 terms, respectively. $$\frac{120}{120}$$ = 1, $$\frac{240}{120}$$ = 2

1 term * average 8.2 = $$Sum_1$$ of 8.2
2 terms * ave. 10.6 = $$Sum_2$$ of 21.2

Total sum: (8.2 + 21.2) = 29.4
Total terms: (1 + 2) = 3

Average = total sum/ total # of terms

$$\frac{29.4}{3}$$ = 9.8, Answer D
_________________
Listen, are you breathing just a little, and calling it a life?
-- Mary Oliver

For practice SC questions with official explanations that were posted and moderated by the SC Team,
go to SC Butler here: https://gmatclub.com/forum/project-sc-butler-get-2-sc-questions-everyday-281043.html
Set A contains 120 terms with an average of 8.2. Set B contains 240   [#permalink] 31 Jul 2017, 07:47
Display posts from previous: Sort by

# Set A contains 120 terms with an average of 8.2. Set B contains 240

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

 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®.