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

 It is currently 23 Mar 2019, 01:51 ### 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

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

Math Expert V
Joined: 02 Sep 2009
Posts: 53795
If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in  [#permalink]

### Show Tags 00:00

Difficulty:   15% (low)

Question Stats: 89% (01:02) correct 11% (01:28) wrong based on 30 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

_________________
CEO  D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2844
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in  [#permalink]

### Show Tags

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

_________________

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

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

examPAL Representative G
Joined: 07 Dec 2017
Posts: 906
Re: If a + b = 9c, and the average (arithmetic mean) of a, b, c, and d in  [#permalink]

### Show Tags

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.
_________________
Intern  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

(a+b+c+d)/4=4c
9c+c+d=16c
So d=6c

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, 11:16
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 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®.  