It is currently 23 Jun 2017, 19:38

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

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

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Director
Joined: 29 Nov 2012
Posts: 878
Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 00:16
3
This post received
KUDOS
1
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

68% (02:55) correct 32% (02:21) wrong based on 284 sessions

### HideShow timer Statistics

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 http://gmatclub.com/forum/gmat-prep-software-analysis-and-what-if-scenarios-146146.html

Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GMAT 1: 700 Q50 V34
GPA: 3.6
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 00:22
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: http://gmatclub.com/forum/vocabulary-list-for-gmat-reading-comprehension-155228.html
learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat-analytical-writing-assessment
: http://www.youtube.com/watch?v=APt9ITygGss

Director
Joined: 29 Nov 2012
Posts: 878
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 00:41
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 http://gmatclub.com/forum/gmat-prep-software-analysis-and-what-if-scenarios-146146.html

Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GMAT 1: 700 Q50 V34
GPA: 3.6
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 00:48
2
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: http://gmatclub.com/forum/vocabulary-list-for-gmat-reading-comprehension-155228.html
learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat-analytical-writing-assessment
: http://www.youtube.com/watch?v=APt9ITygGss

Director
Joined: 17 Dec 2012
Posts: 550
Location: India
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 00:55
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
http://www.sravnatestprep.com

Classroom and Online Coaching

Intern
Joined: 20 Dec 2012
Posts: 4
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 08:30
still i didn't understood why 12/60 and 7/60.....no where they've mentioned 60min right...
please answer
Math Expert
Joined: 02 Sep 2009
Posts: 39622
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

05 Sep 2013, 08:36
1
This post received
KUDOS
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?
_________________
Intern
Joined: 20 Dec 2012
Posts: 4
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

06 Sep 2013, 08:27
Thank you Bunuel.... concept is clear
Intern
Joined: 02 Oct 2012
Posts: 4
GMAT 1: 730 Q49 V41
GPA: 3.73
WE: Project Management (Military & Defense)
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

09 Sep 2013, 06:46
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.
Senior Manager
Joined: 13 May 2013
Posts: 469
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

09 Sep 2013, 09:05
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!

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?

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
Senior Manager
Joined: 10 Mar 2013
Posts: 278
GMAT 1: 620 Q44 V31
GMAT 2: 690 Q47 V37
GMAT 3: 610 Q47 V28
GMAT 4: 700 Q50 V34
GMAT 5: 700 Q49 V36
GMAT 6: 690 Q48 V35
GMAT 7: 750 Q49 V42
GMAT 8: 730 Q50 V39
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

12 Oct 2013, 07:53
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?
Math Expert
Joined: 02 Sep 2009
Posts: 39622
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

12 Oct 2013, 08:56
1
This post received
KUDOS
Expert's post
TooLong150 wrote:
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?

Because t is the usual time, for which Jeff is on time at work.
_________________
Manager
Joined: 15 Aug 2013
Posts: 59
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

12 Oct 2013, 22:19
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
Joined: 13 Aug 2012
Posts: 114
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

14 Oct 2013, 22:54
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
Manager
Joined: 05 Jun 2012
Posts: 108
Schools: IIMA
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

21 Apr 2014, 01:05
Since avg. speed is given in hour ; let t be be original time when Jeff covered the distance.

as we know speed=distance/time; 40(t+12/60)=x and from second 48(t+7/60)=x

equation 1 and 2 40(t+12/60)=48(t+7/60) will give t=.3

to know distance covered put t=.3 in 1st equation 40(.3+.2)=20 So (A)
_________________

If you are not over prepared then you are under prepared !!!

SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1857
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

21 Apr 2014, 03:29
Distance = Speed x Time

Equation (1)

$$d = 40 (t + \frac{12}{60})$$

Equation (2)

$$d = 48 (t+\frac{7}{60})$$

Equating (1) & (2)

$$40 (t + \frac{12}{60}) = 48 (t+\frac{7}{60})$$

$$t = \frac{18}{60}$$

Placing value of t in Equation (1)

$$d = 40 (\frac{18}{60} + \frac{12}{60})$$

$$= 40 * \frac{30}{60}$$

= 20

Answer = A
_________________

Kindly press "+1 Kudos" to appreciate

Current Student
Joined: 14 Jul 2013
Posts: 32
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

24 Apr 2014, 04:24
40(t+12/60) = 48(t+7/60)

solve for t,
=> t = 18/60 or 3/10

now distance = speed*time
i.e. d = 40(3/10 + 1/5) = 20.
Hence, A.
Intern
Joined: 02 Mar 2015
Posts: 32
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

06 Aug 2015, 06:51
Bunuel wrote:
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?

Bunuel pls what if "The next day he left home for work at 10 min late than yesterday"
Math Forum Moderator
Joined: 20 Mar 2014
Posts: 2642
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

06 Aug 2015, 07:22
jimwild wrote:
Bunuel wrote:
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?

Bunuel pls what if "The next day he left home for work at 10 min late than yesterday"

For the original question, let v and t be the speed and time to reach the office without any delays.

Thus distance = vt

Case 1, 12 minutes late:

vt = 40(t+12/60) ...(1)

Case 2, 7 minutes late:

vt = 48(t+7/60) ...(2)

Thus 40(t+12/60) = 48(t+7/60) ---> t = 0.3 hour. Thus the distance = 40 (0.3+12/60) = 20 miles. A is the correct answer.

Now, coming back to your question, if the question said "The next day he left home for work at 10 min late than yesterday" ---> the time that Jim would be late will now be 10+7 = 17 minutes late (as he would be 7 minutes late when he left at the same time , so he would be 17 minutes late if left his home 10 minutes later that yesterday!) and the equations will become :

40(t+12/60) = 48(t+17/60) .
_________________

Thursday with Ron updated list as of July 1st, 2015: http://gmatclub.com/forum/consolidated-thursday-with-ron-list-for-all-the-sections-201006.html#p1544515
Rules for Posting in Quant Forums: http://gmatclub.com/forum/rules-for-posting-please-read-this-before-posting-133935.html
Writing Mathematical Formulae in your posts: http://gmatclub.com/forum/rules-for-posting-please-read-this-before-posting-133935.html#p1096628
GMATCLUB Math Book: http://gmatclub.com/forum/gmat-math-book-in-downloadable-pdf-format-130609.html
Everything Related to Inequalities: http://gmatclub.com/forum/inequalities-made-easy-206653.html#p1582891
Inequalities tips: http://gmatclub.com/forum/inequalities-tips-and-hints-175001.html
Debrief, 650 to 750: http://gmatclub.com/forum/650-to-750-a-10-month-journey-to-the-score-203190.html

Senior Manager
Status: DONE!
Joined: 05 Sep 2016
Posts: 409
Re: Jeff drove to work from this home, averaging 40 miles per ho [#permalink]

### Show Tags

09 Jan 2017, 14:44
Two equations can be created from the prompt using the D = RT equation:

(1) D = (40mi/hr)(t+ 1/5)
(2) D = (48mi/hr)(t+ 7/60)

Plug (1) into (2) --> 40t+8 = D --> 40t+8 = 48t+(28/5)

Simplify --> (40-28)/5 = 8t --> 12/5 = 8t --> 3/10 = t

Plug this back into either of the original equations (i.e. (1) or (2)) and you'll find distance to be 20 mi.

A.
Re: Jeff drove to work from this home, averaging 40 miles per ho   [#permalink] 09 Jan 2017, 14:44
Similar topics Replies Last post
Similar
Topics:
1 Charissa travels from home to work average speed of 60 miles per hour 3 26 Apr 2017, 11:44
2 Adam began driving from home on a trip averaging 30 miles per hour. Ho 1 26 Dec 2016, 12:26
15 Jacob drove from Town A to Town B at an average rate of x miles per ho 6 28 Apr 2017, 15:31
5 Cole drove from home to work at an average speed of 75 kmh. He then 11 30 Jun 2016, 11:53
20 Carol started from home on trip averaging 30 miles per hour. 8 01 Sep 2016, 21:38
Display posts from previous: Sort by

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

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.