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

It is currently 13 Oct 2019, 22:53

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

If the average (arithmetic mean) of a and b is 50 and the average (ari

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58335
If the average (arithmetic mean) of a and b is 50 and the average (ari  [#permalink]

Show Tags

New post 01 Jan 2018, 10:38
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

81% (00:59) correct 19% (00:54) wrong based on 46 sessions

HideShow timer Statistics

Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 3536
If the average (arithmetic mean) of a and b is 50 and the average (ari  [#permalink]

Show Tags

New post 01 Jan 2018, 13:45
Bunuel wrote:
If the average (arithmetic mean) of a and b is 50 and the average (arithmetic mean) of b and c is 70, what is the value of c – a ?

A. 10
B. 20
C. 40
D. 60
E. It cannot be determined from the information given.

If \(\frac{a + b}{2} = 50\), then
\(a + b = 100\), and similarly
\(c + b = 140\)

Subtract first equation from second equation.

\(c + b = 140\)
\(a + b = 100\)
··························
\(c - a = 40\)

Answer
_________________
SC Butler has resumed! Get two SC questions to practice, whose links you can find by date, here.




Choose life.
SVP
SVP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1687
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
Reviews Badge CAT Tests
If the average (arithmetic mean) of a and b is 50 and the average (ari  [#permalink]

Show Tags

New post 02 Jan 2018, 00:30
Bunuel wrote:
If the average (arithmetic mean) of a and b is 50 and the average (arithmetic mean) of b and c is 70, what is the value of c – a ?

A. 10
B. 20
C. 40
D. 60
E. It cannot be determined from the information given.


\(\frac{(a + b)}{2}\) = 50

a + b = 100

b = 100 - a -----> (I)

\(\frac{(b + c)}{2}\) = 70

b + c = 140 ------> (II)

Using equation I & II we get c - a = 40 (C)
_________________
"Do not watch clock; Do what it does. KEEP GOING."
Intern
Intern
avatar
B
Joined: 28 Dec 2017
Posts: 30
Re: If the average (arithmetic mean) of a and b is 50 and the average (ari  [#permalink]

Show Tags

New post 20 Jan 2018, 23:12
(a + b)/2 = 50
Hence, a + b = 100 Equation 1

(b + c)/2 = 70
Hence, b + c = 140 Equation 2

Subtract Equation 1 from Equation 2:
(b + c) - (a + b) = 140 - 100
c - a = 40 (Answer C)
GMAT Club Bot
Re: If the average (arithmetic mean) of a and b is 50 and the average (ari   [#permalink] 20 Jan 2018, 23:12
Display posts from previous: Sort by

If the average (arithmetic mean) of a and b is 50 and the average (ari

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne