Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 19 May 2013, 02:09
Customize  |  Hide

Search
Register
New posts
Unanswered

How many hours did it take Helen to drive from her house to

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
Intern
Intern
Joined: 16 Jul 2008
Posts: 16
Followers: 0

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

How many hours did it take Helen to drive from her house to [#permalink] New post 23 Jul 2008, 22:50
How many hours did it take Helen to drive from her house to her parent's house?

(1) Helen's average speed on this trip was 72 kilometers per hour
(2) If Helen's average speed on this trip had been 8 kilometers per hour greater , it would have taken her 1 hour less.
Manager
Manager
Joined: 03 Jun 2008
Posts: 136
Schools: ISB, Tuck, Michigan (Ross), Darden, MBS
Followers: 1

Kudos [?]: 4 [0], given: 0

Re: Complex rate problem [#permalink] New post 23 Jul 2008, 22:58
Statement 1: Alone is insufficient as distance is unavailable.

Statement 2: Alone is insufficient as neither speed nor distance is available.

Combining Both: From Statement 1 we know that 72 km/hr is the avg. speed. Let the time taken by helen be X.

Thereforhome.e distance travelled by Helen is 72*X

From statement 2, we know that if the speed had been 8 km/hr more than the original it would take 1 hr less.

=> 72X/80 = X-1

Therefore we can solve for X, which is the time take by Helen.
_________________

-----------------------------------------------------------
'It's not the ride, it's the rider'

Manager
Manager
Joined: 14 Jun 2008
Posts: 162
Followers: 1

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

Re: Complex rate problem [#permalink] New post 24 Jul 2008, 03:55
(1) cannot say anything

Let x = time taken in 72 km / hr case

since distance = speed * time

72x = (72 + 8) (x -1)
72x = 80(x - 1)
8x = 80
x = 10

so (2) sufficient

so B
Current Student
Joined: 28 Dec 2004
Posts: 3440
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11

Kudos [?]: 134 [0], given: 2

GMAT Tests User
Re: Complex rate problem [#permalink] New post 24 Jul 2008, 04:05
djdela wrote:
How many hours did it take Helen to drive from her house to her parent's house?

(1) Helen's average speed on this trip was 72 kilometers per hour
(2) If Helen's average speed on this trip had been 8 kilometers per hour greater , it would have taken her 1 hour less.


i suck at Q..what can i say..

D/V=t

D/(v+8)=t+1

Vt=(t+1)(v+8)
vt+8t+v=vt

8t+v=0...we dont know V and and t..

1) we are told v=72

1+2) 8t=72 t=9

i get C..
Manager
Manager
Joined: 14 Jun 2008
Posts: 162
Followers: 1

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

Re: Complex rate problem [#permalink] New post 24 Jul 2008, 04:10
sset009 wrote:
(1) cannot say anything

Let x = time taken in 72 km / hr case

since distance = speed * time

72x = (72 + 8) (x -1)
72x = 80(x - 1)
8x = 80
x = 10

so (2) sufficient

so B

oops used, info from 1
should be C
Senior Manager
Senior Manager
User avatar
Joined: 19 Mar 2008
Posts: 360
Followers: 1

Kudos [?]: 11 [0], given: 0

GMAT Tests User
Re: Complex rate problem [#permalink] New post 24 Jul 2008, 08:45
How many hours did it take Helen to drive from her house to her parent's house?

(1) Helen's average speed on this trip was 72 kilometers per hour
(2) If Helen's average speed on this trip had been 8 kilometers per hour greater , it would have taken her 1 hour less.


(1) alone is NOT sufficient. it just gives speed, no information on time and distance.

(2) alone is NOT sufficient. We can derive a relationship: (let x be speed, t = time)
x*t = (x+8)*(t-1)

(1) +(2), then 72t = 80(t-1)
Sufficient

Ans is C
Re: Complex rate problem   [#permalink] 24 Jul 2008, 08:45
    Similar topics Author Replies Last post
Similar
Topics:
 New posts How many hours did it take Helen to drive to her parents sideslip 3 03 May 2006, 19:14
New posts How many hours did it take Helen to drive from her house to bmiller0731 1 03 Feb 2009, 15:54
New posts EXPERTS_POSTS_IN_THIS_TOPIC How many hours did it take Helen to drive from her house to changhiskhan 8 26 Mar 2010, 17:00
New posts How many hours did it take helen to drive from her house to mydreammba 2 26 Oct 2011, 00:20
New posts 5 EXPERTS_POSTS_IN_THIS_TOPIC How many hours did it take Dale to drive shrive555 6 20 Dec 2011, 07:47
Display posts from previous: Sort by

How many hours did it take Helen to drive from her house to

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma

Search for:


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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com