It is currently 16 Dec 2018, 13:52
My Tests

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.

GRE Math Challenge #11- If a + 2b= 14 and 5a + 4b =16

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4750
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1664 [0], given: 396

CAT Tests
GRE Math Challenge #11- If a + 2b= 14 and 5a + 4b =16 [#permalink] New post 07 Sep 2014, 06:54
Expert's post
00:00

Question Stats:

100% (00:59) correct 0% (00:00) wrong based on 8 sessions
If a + 2b= 14 and 5a + 4b =16, what is the average (arithmetic mean) of a and b?

[Reveal] Spoiler: Answer
5/2

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

1 KUDOS received
GRE Instructor
User avatar
Joined: 10 Apr 2015
Posts: 1246
Followers: 46

Kudos [?]: 1135 [1] , given: 7

Re: GRE Math Challenge #11- If a + 2b= 14 and 5a + 4b =16 [#permalink] New post 01 Sep 2017, 13:44
1
This post received
KUDOS
Expert's post
sandy wrote:
If a + 2b = 14 and 5a + 4b =16, what is the average (arithmetic mean) of a and b?

[Reveal] Spoiler: Answer
5/2


The average (arithmetic mean) of a and b = (a + b)/2

The slow approach to answer this question is to solve the system of equations to find the individual values of a and b.

The fast approach is to recognize that we need only find the SUM of a and b

Here's what I mean...

Given:
a + 2b = 14
5a + 4b =16

ADD the two equations to get:
6a + 6b = 30

Factor to get:
6(a + b) = 30

Divide both sides by 6 to get:
a + b = 5

Divide both sides by 2 to get:
(a + b)/2 = 5/2

Perfect!
The average (arithmetic mean) of a and b = (a + b)/2, and we can see that (a + b)/2 = 5/2

Answer: 5/2

RELATED VIDEOS



_________________

Brent Hanneson – Creator of greenlighttestprep.com
Image
Sign up for our free GRE Question of the Day emails

Re: GRE Math Challenge #11- If a + 2b= 14 and 5a + 4b =16   [#permalink] 01 Sep 2017, 13:44
Display posts from previous: Sort by

GRE Math Challenge #11- If a + 2b= 14 and 5a + 4b =16

  Question banks Downloads My Bookmarks Reviews Important topics  


GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.