BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

average problem- any solun by plugging of nos

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 62
Joined: Wed May 04, 2011 9:50 pmFollowed by: 2 members
Thanked: 2 times
by kishokbabu » Tue Dec 13, 2011 9:36 am
If W>Y, the average of X and Y is Z, and the average of Z and X is W, what is the value of (X-W)/(W-Y)=?

a) 1/4
b) 1/3
c) 1/2
d) 3
e) 4

Correct Answer .: B

Kindly suggest whether plugging of numbers will work for this problem and some better option to solve it in easy ways?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Legendary Member
Posts: 966
Joined: Sat Jan 02, 2010 8:06 amFollowed by: 21 members
Thanked: 230 times

by shankar.ashwin » Tue Dec 13, 2011 9:40 am
W,X,Y and Z are 4 variables used.

Average of X and Y is Z

Let X = 0, Y = 2. Therefore Z = 1

Average of Z and X is W

Z = 1 and X = 0. Therefore W = 1/2

You're asked (X-W)/(W-Y) = (0-1/2) / (1/2-2) = -1/2 / (-3/2) = [spoiler]1/3 [/spoiler]
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 588
Joined: Sun Oct 16, 2011 9:42 amFollowed by: 9 members
Location: New Delhi, India
Thanked: 130 times
GMAT Score:720

by rijul007 » Tue Dec 13, 2011 10:06 am
The best approach to do this question is by plugging in numbers

Let us say x = 40 and y = 20
Avg of x and y = z = (20+40)/2 = 30

Avg of z and x = w = (20+30)/2 = 35

(x-w)/(w-y) = (40-35)/(35-20) = 5/15 = 1/3

Option B
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 62
Joined: Wed May 04, 2011 9:50 pmFollowed by: 2 members
Thanked: 2 times

by kishokbabu » Tue Dec 13, 2011 10:11 am
HI shankar.ashwin

As per your plugging of numbers it does not match with the question,

As per qn, W should be greater than Y, but in your plugging you got W=1/2 and Y=2 this is wrong.

Iam not sure whether the qn is correct r wrong. If the condition W>Y is not given in qn then your approach is correct.

So any one pls check if W> Y then we can get the same answer as 1/3.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Sun Dec 04, 2011 10:02 pm
Thanked: 2 times

by Mdewan » Tue Dec 13, 2011 10:12 am
The problem states W>Y,
Equation 1: X+Y/2=Z
Equation 2: Z+X/2=w

Solving Equation 1 & 2
X+Y=2Z Z+X=2w => Z=2W-X

X+Y=2(2W-X)
3X+Y=4W => X=(4W-Y)/3...Equation 3

We need to find (x-w)/(w-y)
Sub Equation 3 to solve

((4W-Y)/3 -W)/ (W-Y)
= 1/3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 588
Joined: Sun Oct 16, 2011 9:42 amFollowed by: 9 members
Location: New Delhi, India
Thanked: 130 times
GMAT Score:720

by rijul007 » Tue Dec 13, 2011 10:22 am
kishokbabu wrote:HI shankar.ashwin

As per your plugging of numbers it does not match with the question,

As per qn, W should be greater than Y, but in your plugging you got W=1/2 and Y=2 this is wrong.

Iam not sure whether the qn is correct r wrong. If the condition W>Y is not given in qn then your approach is correct.

So any one pls check if W> Y then we can get the same answer as 1/3.

The statement W>Y .. doesnt really play any part in the solution
Because either way we would get the same solution

W>Y would correspond to X>Y which further means X>W
So (X-W)/(W-Y)= +ve

W<Y corresponds to Y>X which further means X<W
(X-W)/(W-Y)= -ve/-ve = +ve [The magnitude remaining the same]
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 966
Joined: Sat Jan 02, 2010 8:06 amFollowed by: 21 members
Thanked: 230 times

by shankar.ashwin » Tue Dec 13, 2011 10:26 am
Sorry didnt notice that while reading. But as rijul pointed out, the solution remains the same, just pick up a set of numbers which satisfy W>Y, you would still get the same answer for this question
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1