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

It is currently 19 May 2019, 01:35

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

On a particular exam, the boys in a history class averaged 86 points a

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

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55150
On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 05:05
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

76% (01:08) correct 24% (01:34) wrong based on 228 sessions

HideShow timer Statistics

Manager
Manager
avatar
Joined: 20 Jul 2011
Posts: 80
GMAT 1: 660 Q49 V31
GMAT ToolKit User
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 10:03
2
Bunuel wrote:
On a particular exam, the boys in a history class averaged 86 points and the girls in the class averaged 80 points. If the overall class average was 82 points, what was the ratio of boys to girls in the class?

A. 1:4
B. 1:3
C. 1:2
D. 2:1
E. 3:1

Kudos for a correct solution.



Solution: We can use the X method to solve similar questions

B...................G
86................80

..........82........

2..................4

Hence, Boys: Girls => 2: 4 => 1:2

Option C
Manager
Manager
User avatar
B
Joined: 26 Dec 2011
Posts: 115
Schools: HBS '18, IIMA
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 06:07
1
3
On a particular exam, the boys in a history class averaged 86 points and the girls in the class averaged 80 points. If the overall class average was 82 points, what was the ratio of boys to girls in the class?

A. 1:4
B. 1:3
C. 1:2
D. 2:1
E. 3:1

Solution -

Given that Boys average is 86 and Girls average is 80 points. Total average is 82 points.

(86B+80G)/(B+G) = 82 --> 4B=2G --> B/G = 1/2. ANS C.
_________________
Thanks,
Kudos Please
Retired Moderator
avatar
B
Status: On a mountain of skulls, in the castle of pain, I sit on a throne of blood.
Joined: 30 Jul 2013
Posts: 305
GMAT ToolKit User Reviews Badge
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 07:13
1
Bunuel wrote:
On a particular exam, the boys in a history class averaged 86 points and the girls in the class averaged 80 points. If the overall class average was 82 points, what was the ratio of boys to girls in the class?

A. 1:4
B. 1:3
C. 1:2
D. 2:1
E. 3:1

Kudos for a correct solution.


G B
80 86
82
4 2
2 : 1

G:B=2:1
B:G=1:2

Answer: C
Manager
Manager
avatar
B
Joined: 26 Dec 2012
Posts: 146
Location: United States
Concentration: Technology, Social Entrepreneurship
WE: Information Technology (Computer Software)
On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post Updated on: 30 Jun 2015, 11:20
1
Let # boys in the class=x & # of girls in class =y
so we have (sum of boys)=86X
(sum of girls)=80y

total average =82=>
86x+80y=82(x+y) =? we get 4x=2y
so x/y =1/2

Hence answer is C
Thanks,

Originally posted by lipsi18 on 30 Jun 2015, 10:30.
Last edited by lipsi18 on 30 Jun 2015, 11:20, edited 1 time in total.
Manager
Manager
User avatar
Joined: 18 Mar 2014
Posts: 227
Location: India
Concentration: Operations, Strategy
GMAT 1: 670 Q48 V35
GPA: 3.19
WE: Information Technology (Computer Software)
GMAT ToolKit User
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 11:01
1
1
86 ----------- 80
-------82-----------
2-------------- 4 .... hence 2:4 = 1:2

Did cross subtraction here ,
86-82 = 4 , 82-80 = 2

Required answer = 1:2
C
_________________
Press +1 Kudos if you find this Post helpful :)
Manager
Manager
avatar
Joined: 07 Apr 2015
Posts: 162
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 01 Jul 2015, 07:51
1
I think its 2:1 as question asks for the ratio of Boys to girls.

Let x be number of boys, y number of girls.

86x + 80y / (x+y) = 82

86x + 80y = 82x + 82y
4x = 2y
2x = y
2:1
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55150
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 06 Jul 2015, 02:59
1
Bunuel wrote:
On a particular exam, the boys in a history class averaged 86 points and the girls in the class averaged 80 points. If the overall class average was 82 points, what was the ratio of boys to girls in the class?

A. 1:4
B. 1:3
C. 1:2
D. 2:1
E. 3:1

Kudos for a correct solution.


MANHATTAN GMAT OFFICIAL SOLUTION:

The boys in the class scored 4 points higher on average than the entire class. The boys have a + 4 differential. Similarly, the girls scored 2 points lower on average than the class. They have a - 2 differential. You need to balance out the differentials:

b*(+4) + g*(-2) = 0

If b = 1 and g = 2, the equation will be true. Thus, the ratio of boys to girls is 1:2.

Answer: C.
_________________
Senior Manager
Senior Manager
User avatar
B
Joined: 28 Jun 2015
Posts: 290
Concentration: Finance
GPA: 3.5
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 30 Jun 2015, 10:37
80 - 82 - 86

86-82/82-80 = 4/2 = 2/1. D.
_________________
I used to think the brain was the most important organ. Then I thought, look what’s telling me that.
Intern
Intern
avatar
Joined: 13 May 2015
Posts: 18
Concentration: Finance, General Management
GMAT 1: 330 Q17 V12
GPA: 3.39
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 06 Oct 2016, 05:40
I got that 86-82 & 82-80 are the two sets of numbers we are using to arrive at the answer however im getting 2:1 and not 1:2..... help!
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2616
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 10 Dec 2016, 10:26
Senior Manager
Senior Manager
User avatar
G
Joined: 14 Feb 2017
Posts: 269
Location: Australia
Concentration: Technology, Strategy
GMAT 1: 560 Q41 V26
GMAT 2: 550 Q43 V23
GPA: 2.61
WE: Management Consulting (Consulting)
CAT Tests
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 01 Aug 2017, 03:22
I can't seem to apply a consistent approach to weighted average problems.

Could someone please point me to the right direction for a good explanation of the approach?
Manager
Manager
User avatar
G
Joined: 30 May 2012
Posts: 201
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 07 Aug 2017, 09:26
ashokk138 wrote:
Bunuel wrote:
On a particular exam, the boys in a history class averaged 86 points and the girls in the class averaged 80 points. If the overall class average was 82 points, what was the ratio of boys to girls in the class?

A. 1:4
B. 1:3
C. 1:2
D. 2:1
E. 3:1

Kudos for a correct solution.



Solution: We can use the X method to solve similar questions

B...................G
86................80

..........82........

2..................4

Hence, Boys: Girls => 2: 4 => 1:2

Option C


I have come across this - "X - method" in several posts on this forum. Is there a theory/article describing this? Seems like a sure shot approach to weighted averages. Can someone point me to the resource, please?
Manager
Manager
avatar
B
Joined: 24 Jun 2017
Posts: 121
Re: On a particular exam, the boys in a history class averaged 86 points a  [#permalink]

Show Tags

New post 07 Aug 2017, 12:22
lets x be the number of boys and y number of girls
(86x + 80y) / (x + y) = 82
86x + 80 y = 82x + 82y
86x - 82x = 82y - 80y
4x = 2y
2x = y

1:2 (boys:girls)
GMAT Club Bot
Re: On a particular exam, the boys in a history class averaged 86 points a   [#permalink] 07 Aug 2017, 12:22
Display posts from previous: Sort by

On a particular exam, the boys in a history class averaged 86 points a

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.