then a – c =

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

then a – c =

by sanju09 » Wed Sep 15, 2010 9:23 pm
If the average (arithmetic mean) of a and b is 45, and the average (arithmetic mean) of b and c is 35, then a - c =
(A) 5
(B) 10
(C) 20
(D) 30
(E) 40

[spoiler]Source: https://readyforgmat.com[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1179
Joined: Sun Apr 11, 2010 9:07 pm
Location: Milpitas, CA
Thanked: 447 times
Followed by:88 members

by Rahul@gurome » Wed Sep 15, 2010 10:57 pm
(a + b)/2 = 45 implies a + b = 90 -> Equation (1)
(b + c)/2 = 35 implies b + c = 70 -> Equation (2)
Subtracting equation from (2) from (1), we get,
a - c = 20

The correct answer is [spoiler](C)[/spoiler].
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)