Find all School-related info fast with the new School-Specific MBA Forum

It is currently 25 Jul 2014, 01:11

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

rate problem

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 23 Jan 2011
Posts: 128
Followers: 1

Kudos [?]: 9 [0], given: 12

rate problem [#permalink] New post 31 May 2011, 14:26
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 100% (00:36) wrong based on 5 sessions
A cold water tube can fulfill a pool in C hours; a hot water tube can fulfill it in H hours. C<H. Two tubes together can fulfill the pool in T hours. Which of the following must be true?

I. 0<T<H
II. C<T<H
III. C/2 < T < H/2

A. I only
B. II Only
C. III Only
D. I and III only
E. I, II and III
Senior Manager
Senior Manager
avatar
Joined: 24 Mar 2011
Posts: 469
Location: Texas
Followers: 4

Kudos [?]: 52 [0], given: 20

Re: rate problem [#permalink] New post 31 May 2011, 20:42
given C < H.

option 1 - yes ; because T will be less than H. And also C, H and T must be positive.
option 2 - No; because T will be less than values of C and H
option 3 - Yes; because T will be less than values of C and H but 2T will be greater than C and less than H.

these can be proved using example

let C be 2 hrs and H be 3 hrs.
T will be 1/ (1/2 + 1/3) = 6/5 hrs. this satisfies option I and option III.

let C be 40 mins and H be 50 mins.
T will be 1/(1/40 + 1/50) = 200/9 ~ roughly >20 mins
this also satisfies option I and III.

i will go with D.
Manager
Manager
User avatar
Status: Preparing myself to break the sound( 700 )-barrier!
Affiliations: IFC - Business Edge, Bangladesh Enterprise Institute
Joined: 15 Feb 2011
Posts: 209
Location: Dhaka, Bangladesh
Schools: Texas A&M - Mays; PennState - Smeal; Purdue - Krannert; JohnsHopkins - Carey; Vanderbilt - Owen; WakeForest - Babcock; UBC - Sauder
WE 1: Financial Analyst/Financial Management Trainer - BRAC Afghanistan - 13 months
WE 2: Business Proposal Coordinator - MiDS, Inc. (in Kabul, Afghanistan) - 4 Months (did quit the job bcoz of security concerns)
WE 3: Readers For Readers (A Social Impact Generating Organization) - Co-Founder
Followers: 7

Kudos [?]: 30 [0], given: 136

Re: rate problem [#permalink] New post 31 May 2011, 21:00
My shot is for option D.

Here is why:
This problem can be solved as working-together problem. Let's say, C=5 hours and H=6 hours. If both the tubes are open together, the pool will be filled in (5*6)/(5+6)=2.7 hours(apprx.) i.e. T=2.7 hours. This answer gives validity to options I and III. So, D is the shot.
Then, again, let's say, C=1 hours and H=9 hours. If both the tubes are open together, the pool will be filled in (1*9)/(1+9)=0.9 hours i.e. T=0.9 hours. This answer validates the options I and III, once again. Thus, D is the shot.
(though not necessary anymore) In this way, if you take any positive number, whether faction or integer, answer option I and III will be always valid for this question.
Thank you.
VP
VP
avatar
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1365
Followers: 10

Kudos [?]: 131 [0], given: 10

GMAT Tests User
Re: rate problem [#permalink] New post 13 Jun 2011, 00:11
rc = 2 rh = 3,4

t = 6/5 , 4/3.

only A prevails.
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Current Student
avatar
Joined: 26 May 2005
Posts: 571
Followers: 18

Kudos [?]: 98 [0], given: 13

GMAT Tests User
Re: rate problem [#permalink] New post 13 Jun 2011, 03:57
amit2k9 wrote:
rc = 2 rh = 3,4

t = 6/5 , 4/3.

only A prevails.


Hi Amit,
Not sure if u meant this :

C= 2 and H = 3.4

1/2+1/3.4= 17/34+10/34 = 27/34
t = 34/27 = 1.26
in this case both 1 and 3 are right .. isnt it?
Re: rate problem   [#permalink] 13 Jun 2011, 03:57
    Similar topics Author Replies Last post
Similar
Topics:
2 Rate Problem Yalephd 3 08 Aug 2010, 18:23
Rate problem aljooyidan 3 18 May 2010, 12:38
Rate Problem olive 3 30 Jun 2008, 14:54
Rate problem ryomkg 5 02 Dec 2006, 20:30
RATE PROBLEM rointy 3 09 Sep 2006, 05:43
Display posts from previous: Sort by

rate problem

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.