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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

value of K

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 871
Joined: Wed Aug 13, 2008 7:48 am
Thanked: 48 times

by stop@800 » Thu Sep 25, 2008 11:13 pm
The question is incomplete.

Please correct it.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Thu Sep 25, 2008 11:37 pm
If x, y, and k are positive numbers such that (x/x+y)10+(y/x+y)(20) = k and if x < y, which of the following could be the value of k?

A. 10
B. 12
C. 15
D. 18
E. 30
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Fri Aug 24, 2007 3:11 pm
Location: INDIA

by narayanj » Fri Sep 26, 2008 3:24 am
Take x=1 and y=4 to get the answer
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Fri Sep 26, 2008 4:34 am
howcm u arrived at x=1 and y=4.pls explain
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 871
Joined: Wed Aug 13, 2008 7:48 am
Thanked: 48 times

by stop@800 » Fri Sep 26, 2008 7:32 am
Soln
= (x/x+y)10+(y/x+y)(20)
= 10(x/x+y)+10(y/x+y)+10(y/x+y)
= 10(x+y)/(x+y) + 10(y/x+y)
= 10 + 10 (y/x+y)


since x and y are positive so
the answer will certainly be greater than 10
A is out


since y > x

so y/(x+y) will always be greater than 1/2
had y been equal to x, the value could have been equal to 1/2

so 12 and 15 are also out


Now we are left with 18 and 30

y/(x+y) will always be less than 1
it can never be greater
so 30 is out

we are left with 18, the answer :)


You will not require this much effort evrytime, once you are through with the concept, by looking at statement you will be able to judge
that result is between 15 and 20 [non inclusive]


Also,
No offenses but I personally dont like number substitution.

If you want to do with substitution, you can do so

choose any set of numbers and solve
than take another set and solve

you will find the result to be between 15 - 20
and
if u r fortunate you may get 1 and 4 as your first choice and 18 as answer.


Hope this helps!!!
vivek.kapoor83 wrote:howcm u arrived at x=1 and y=4.pls explain
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 45
Joined: Wed Sep 03, 2008 5:32 am

by icandy018 » Fri Sep 26, 2008 8:08 am
= 10(x/x+y)+10(y/x+y)+10(y/x+y)
= 10(x+y)/(x+y) + 10(y/x+y)

how did you go from the first line to the second. I dont understand.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 105
Joined: Tue Jul 15, 2008 7:03 pm
Thanked: 5 times

by pre-gmat » Fri Sep 26, 2008 8:57 am
Good explanation Stop at 800.


= 10(x/x+y)+10(y/x+y)+10(y/x+y)
= 10(x+y)/(x+y) + 10(y/x+y)


10(x/x+y)+10(y/x+y) is same as 10(x+y)/x+y
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 45
Joined: Wed Sep 03, 2008 5:32 am

by icandy018 » Fri Sep 26, 2008 9:05 am
I dont see how.

10 (1/y) + 10(1/x) is the only thing i see with combining those too.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2623
Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members
Location: Montreal
Thanked: 1090 times
GMAT Score:780

by Ian Stewart » Fri Sep 26, 2008 10:05 am
I gave a short, albeit very conceptual, solution here:

www.beatthegmat.com/number-system-sets-t14684.html
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Thu Jan 08, 2009 12:36 am
OA is 18
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 60
Joined: Mon Jun 04, 2007 7:37 am
Thanked: 6 times

by sonu_thekool » Fri Jan 09, 2009 10:51 am
Ian Stewart wrote:I gave a short, albeit very conceptual, solution here:

www.beatthegmat.com/number-system-sets-t14684.html
Ian, thanks for the great explanation in your other post.

On a general note, could you please let us know how to recognize a problem to be weighted averages and apply these techniques to different situations. Especially, when not to use weighted averages to solving problems.

Thanks for all your help.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1