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

It is currently 18 Apr 2014, 16:07

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

Jeff drove to work from this home, averaging 40 miles per ho

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
3 KUDOS received
Director
Director
Joined: 29 Nov 2012
Posts: 936
Followers: 11

Kudos [?]: 157 [3] , given: 543

Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 04 Sep 2013, 23:16
3
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

58% (02:33) correct 41% (02:22) wrong based on 93 sessions
Jeff drove to work from this home, averaging 40 miles per hour and was 12 minutes late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Jeff's home to his work?

a) 20.0
b) 24.5
c) 30.0
d) 37.5
e) 40.0
[Reveal] Spoiler: OA

_________________

Click +1 Kudos if my post helped...

Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/

GMAT Prep software What if scenarios gmat-prep-software-analysis-and-what-if-scenarios-146146.html

1 KUDOS received
Director
Director
User avatar
Joined: 14 Dec 2012
Posts: 836
Location: India
Concentration: Finance, Real Estate
GMAT 1: 640 Q49 V29
GMAT 2: 670 Q50 V29
GMAT 3: 620 Q49 V26
GMAT 4: 700 Q50 V34
GPA: 3.6
Followers: 35

Kudos [?]: 481 [1] , given: 196

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 04 Sep 2013, 23:22
1
This post received
KUDOS
fozzzy wrote:
Jeff drove to work from this home, averaging 40 miles per hour and was 12 minutes late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Jeff's home to his work?

a) 20.0
b) 24.5
c) 30.0
d) 37.5
e) 40.0


LET DISTANCE = D

if T IS REQUIRED TIME TO REACH .

T = \frac{D}{40} - \frac{12}{60} = \frac{D}{48} - \frac{7}{60}
SOLVING D = 20

hence A
_________________

When you want to succeed as bad as you want to breathe ...then you will be successfull....

GIVE VALUE TO OFFICIAL QUESTIONS...



GMAT RCs VOCABULARY LIST: vocabulary-list-for-gmat-reading-comprehension-155228.html
learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat- ... assessment
: http://www.youtube.com/watch?v=APt9ITygGss

Director
Director
Joined: 29 Nov 2012
Posts: 936
Followers: 11

Kudos [?]: 157 [0], given: 543

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 04 Sep 2013, 23:41
I didn't understand the equations but great method! Please elaborate..

\frac{12}{60} the reason you are subtracting is because its \frac{12 minutes}{60 minutes} late?
_________________

Click +1 Kudos if my post helped...

Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/

GMAT Prep software What if scenarios gmat-prep-software-analysis-and-what-if-scenarios-146146.html

1 KUDOS received
Director
Director
User avatar
Joined: 14 Dec 2012
Posts: 836
Location: India
Concentration: Finance, Real Estate
GMAT 1: 640 Q49 V29
GMAT 2: 670 Q50 V29
GMAT 3: 620 Q49 V26
GMAT 4: 700 Q50 V34
GPA: 3.6
Followers: 35

Kudos [?]: 481 [1] , given: 196

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 04 Sep 2013, 23:48
1
This post received
KUDOS
fozzzy wrote:
I didn't understand the equations but great method! Please elaborate..

\frac{12}{60} the reason you are subtracting is because its \frac{12 minutes}{60 minutes} late?

Let say
jeff need to reach in time T.
LET distance to office = d
now first day time taken by jeff = distance/speed = d/40
this time is 12 minutes more than T
therefore T = d/40 -12/60

SIMILARLY second day time taken by jeff = d/48
This is 7 minute more than T
Therefore T = d/40-7/60

NOW EQUATING both equation of T.
\frac{d}{40} -\frac{12}{60} = \frac{d}{40}-\frac{7}{60}

solving D = 20

hope it helps
_________________

When you want to succeed as bad as you want to breathe ...then you will be successfull....

GIVE VALUE TO OFFICIAL QUESTIONS...



GMAT RCs VOCABULARY LIST: vocabulary-list-for-gmat-reading-comprehension-155228.html
learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat- ... assessment
: http://www.youtube.com/watch?v=APt9ITygGss

Senior Manager
Senior Manager
User avatar
Joined: 17 Dec 2012
Posts: 359
Location: India
Followers: 9

Kudos [?]: 128 [0], given: 8

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 04 Sep 2013, 23:55
fozzzy wrote:
Jeff drove to work from this home, averaging 40 miles per hour and was 12 minutes late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Jeff's home to his work?

a) 20.0
b) 24.5
c) 30.0
d) 37.5
e) 40.0


You may equate distance also

i.e., 40*(t+12/60) = 48* (t+7/60)

You get t=18/60

d= 40*(18/60+12/60) = 20 miles
_________________

Srinivasan Vaidyaraman
sravna@gmail.com

Sravna Test Prep
http://www.sravna.com
Online courses and 1-on-1 Online Tutoring for the GMAT and the GRE

Intern
Intern
Joined: 20 Dec 2012
Posts: 4
Followers: 0

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

CAT Tests
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 05 Sep 2013, 07:30
still i didn't understood why 12/60 and 7/60.....no where they've mentioned 60min right...
please answer
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 17317
Followers: 2874

Kudos [?]: 18379 [0], given: 2348

GMAT Tests User CAT Tests
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 05 Sep 2013, 07:36
Expert's post
praneeth4u wrote:
Jeff drove to work from this home, averaging 40 miles per hour and was 12 minutes late. The next day he left home for work at the same time, took the same route, averaging 48 miles per hour, and was 7 minutes late. How far in miles is it from Jeff's home to his work?

a) 20.0
b) 24.5
c) 30.0
d) 37.5
e) 40.0


still i didn't understood why 12/60 and 7/60.....no where they've mentioned 60min right...
please answer


The point is that the rates are given in miles per hour. So, we are converting 12 and 7 minutes into hours:

12 minutes = 12/60 hours.
7 minutes = 7/60 hours.

Does this make any sense?
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Intern
Intern
Joined: 20 Dec 2012
Posts: 4
Followers: 0

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

CAT Tests
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 06 Sep 2013, 07:27
Thank you Bunuel.... concept is clear :)
Intern
Intern
Joined: 02 Oct 2012
Posts: 4
GMAT 1: 730 Q49 V41
GPA: 3.73
WE: Project Management (Military & Defense)
Followers: 0

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

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 09 Sep 2013, 05:46
I tried a different method here:
I used the following thought process...if the two day trips differed in time by 5 min (12 min late vs. 7 min late), then we can set up the two time equations and set them equal to 5 min or 1/12 hrs.

d/40 - d/48 = 1/12 (5 min); common denominator is 240, so we have (6d-5d) / 240 = 1/12 hr.

if we solve for d, we get: d / 240 = 1/12; 12d = 240 therefore, d = 20 miles.

Choose A.
1 KUDOS received
Senior Manager
Senior Manager
User avatar
Joined: 13 May 2013
Posts: 476
Followers: 0

Kudos [?]: 35 [1] , given: 134

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 09 Sep 2013, 08:05
1
This post received
KUDOS
blueseas wrote:
fozzzy wrote:
I didn't understand the equations but great method! Please elaborate..

\frac{12}{60} the reason you are subtracting is because its \frac{12 minutes}{60 minutes} late?

Let say
jeff need to reach in time T.
LET distance to office = d
now first day time taken by jeff = distance/speed = d/40
this time is 12 minutes more than T
therefore T = d/40 -12/60

SIMILARLY second day time taken by jeff = d/48
This is 7 minute more than T
Therefore T = d/40-7/60

NOW EQUATING both equation of T.
\frac{d}{40} -\frac{12}{60} = \frac{d}{40}-\frac{7}{60}

solving D = 20

hope it helps



I have a quick question.

For T = d/40 -12/60, why wouldn't we add 12/60 (i.e. 12 minutes) to the d/40? After all, doesn't his time increase with his slower speed of d/40?

Thanks! :-D

Edit: I think I got it!

Let's pretend he needs to get home in 60 minutes. The time he takes on the first day works out to be 72 minutes. From this we subtract 12 minutes to even out the equation. "T" represents his time if he is on time. d/40 represents his time on the day in question (which will be greater than his regular time) and 12/60 or 7/60 represents the extra time he took, if subtracted from his slower time would represent his normal time.

Does that make sense? :-D

First day: t = d/40 - 12/60
Second day: t = d/48 - 7/60

d/40 - 12/60 = d/48 - 7/60
d/40 = d/48 + 5/60

(LCM of 40 and 48 is 240)

d = 40*(d/48) + 40*(5/60)
d = 40d/48 + 200/60
d = 200d/240 + 800/240
d = (200d+800)/240
240d = 200d+800
40d = 800
d = 20

ANSWER: 20
Manager
Manager
User avatar
Joined: 10 Mar 2013
Posts: 104
Followers: 0

Kudos [?]: 2 [0], given: 784

CAT Tests
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 12 Oct 2013, 06:53
I had the following:
d = (t + 12/60)*40
d = (t + 7/60)*48

However, I don't understand why the t's have to be same. Can someone explain?
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 17317
Followers: 2874

Kudos [?]: 18379 [1] , given: 2348

GMAT Tests User CAT Tests
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 12 Oct 2013, 07:56
1
This post received
KUDOS
Expert's post
1 KUDOS received
Intern
Intern
Joined: 15 Aug 2013
Posts: 42
Followers: 0

Kudos [?]: 7 [1] , given: 4

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 12 Oct 2013, 21:19
1
This post received
KUDOS
Let 't' is the usual time taken(without getting late)... Since the ration of speed in both case is 40:48 ie 5:6 , the ratio of time taken will be reverse ie 6/5. SO t+12 / t+ 7 = 6/5 giving t = 18 mins. substitute in any - D= 40*(18+12)/60 = 20 miles
divide by 60 to change into hour...
Manager
Manager
Joined: 13 Aug 2012
Posts: 69
Followers: 0

Kudos [?]: 7 [0], given: 63

Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink] New post 14 Oct 2013, 21:54
Let T be the time when Jeff is not late for work

When Jeff is 12 minutes or \frac{1}{5} hours late, Time= T+\frac{1}{5}
Distance= 40(T+\frac{1}{5})-------------------------------------------------------------------------------------(1)

When jeff is 7 minutes or \frac{7}{60} hours late, Time= T+\frac{7}{60}
Distance= 48(T+\frac{7}{60})------------------------------------------------------------------------------------(2)

Equating (1) & (2)

40(T+\frac{1}{5})=48(T+\frac{7}{60})
5T+1=6T+\frac{7}{10}
T=\frac{3}{10}--------------------------------------------------------------------------------------------------------(3)

Putting (3) in (1)
Distance= 40(\frac{3}{10}+\frac{1}{5})= 20miles

A is the answer
Re: Jeff drove to work from this home, averaging 40 miles per ho   [#permalink] 14 Oct 2013, 21:54
    Similar topics Author Replies Last post
Similar
Topics:
New posts 1 susan drove at an average speed of 30 miles per hour for the lan583 4 25 Aug 2006, 09:02
New posts You travel from home to work at 50 miles per hour. As soon Hayabusa 5 03 Jul 2007, 13:57
New posts aaron will jog from home at x miles per hour and then walk chronolinkz 3 26 Aug 2007, 10:02
New posts 3 Experts publish their posts in the topic Susan drove an average speed of 30 miles per hour for the anilnandyala 8 02 Nov 2010, 05:56
New posts 4 Experts publish their posts in the topic Carol started from home on trip averaging 30 miles per hour. cv3t3l1na 5 25 Nov 2012, 04:57
Display posts from previous: Sort by

Jeff drove to work from this home, averaging 40 miles per ho

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.