It is currently 23 Jan 2018, 08:07

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43377
If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in [#permalink]

Show Tags

New post 21 Dec 2017, 03:14
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

89% (00:25) correct 11% (00:00) wrong based on 18 sessions

HideShow timer Statistics

If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in terms of c is 4c, then what is d in terms of c?

A. c/3
B. 2c
C. 5c/2
D. 5c
E. 6c
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Expert Post
SVP
SVP
User avatar
G
Joined: 08 Jul 2010
Posts: 1923
Location: India
GMAT: INSIGHT
WE: Education (Education)
Reviews Badge
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in [#permalink]

Show Tags

New post 21 Dec 2017, 05:00
Bunuel wrote:
If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in terms of c is 4c, then what is d in terms of c?

A. c/3
B. 2c
C. 5c/2
D. 5c
E. 6c


a + b = 9c,

Also, (a+b+c+d)/4 = 4c

i.e. (a+b+c+d) = 16c

i.e. (9c+c+d) = 16c

i.e. 10c+d = 16c

i.e. d = 6c

Answer: option E
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Expert Post
examPAL Representative
User avatar
B
Joined: 07 Dec 2017
Posts: 122
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in [#permalink]

Show Tags

New post 21 Dec 2017, 09:55
Bunuel wrote:
If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in terms of c is 4c, then what is d in terms of c?

A. c/3
B. 2c
C. 5c/2
D. 5c
E. 6c


Since the equations in the question look simple (no powers or roots), we'll go for an exact (Precise) approach.
Writing down the details of our question as equations gives:
a + b = 9c
(a + b + c + d) / 4 = 4c
Substituting equation (1) into (2) and multiplying by 4 gives 9c + c + d = 16c
Then d = 6c.

(E) is our answer.
_________________

David
Senior tutor at examPAL
Signup for a free GMAT course
Image
Image

Intern
Intern
User avatar
B
Joined: 28 May 2017
Posts: 18
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in [#permalink]

Show Tags

New post 21 Dec 2017, 10:16
(a+b+c+d)/4=4c
9c+c+d=16c
So d=6c
E answer


Sent from my iPhone using GMAT Club Forum
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in   [#permalink] 21 Dec 2017, 10:16
Display posts from previous: Sort by

If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.