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 →

nice question

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 1112
Joined: Sat Feb 26, 2011 11:16 amFollowed by: 49 members
Thanked: 77 times
by atulmangal » Mon Apr 25, 2011 10:04 pm
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8 ?

(1) y > 0.15
(2) C >= 7.30
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members
Location: Milpitas, CA
Thanked: 1854 times
GMAT Score:770

by Anurag@Gurome » Mon Apr 25, 2011 10:59 pm
atulmangal wrote:One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8 ?

(1) y > 0.15
(2) C >= 7.30
x + y = 1
C = 6.5x + 8.5y
(1) y > 0.15 does not give a definite answer if x < 0.8.
So, (1) is NOT SUFFICIENT.

(2) C ≥ 7.30 implies C = 6.5x + 8.5(1 - x) = 6.5x + 8.5 - 8.5x ≥ 7.30
8.5 - 2x ≥ 7.3
2x ≤ 1.2
x ≤ 0.6
So, x ≤ 0.6, which implies x < 0.8
So, (2) is SUFFICIENT.

The correct answer is B.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 965
Joined: Thu Jan 28, 2010 12:52 amFollowed by: 34 members
Thanked: 156 times
GMAT Score:720

by vineeshp » Mon Apr 25, 2011 11:07 pm
1) if y = 0.15 x=0.85
if y = 0.3 x=0.7

Not sufficient.

2) C >= 7.30

At x =0.8 y =0.2

C = 6.9. If you increase x from this point, the value of C will only decrease as the coeff of x is smaller than coeff of y. Hence x has to be less than this.
hence sufficient.


To ilustrate

6.5x + 8.5(1-x) = 7.3

1.2 = 2x
x = 0.6

If you increase x from this point, value of C will decrease. So for it to stay above, x has to be <= 0.6.

hence B is sufficient.
Vineesh,
Just telling you what I know and think. I am not the expert. :)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1