Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

It is currently 27 May 2017, 12:51

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Three runners A, B and C run a race, with runner A finishing 12m ahead

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

Hide Tags

Senior Manager
Senior Manager
User avatar
Joined: 03 Mar 2010
Posts: 440
Schools: Simon '16 (M)
Followers: 5

Kudos [?]: 305 [0], given: 22

Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 19 Sep 2011, 09:27
12
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

67% (03:15) correct 33% (02:48) wrong based on 147 sessions

HideShow timer Statistics

Three runners A, B and C run a race, with runner A finishing 12m ahead of runner B and 18m ahead of runner C, while runner B finishes 8m ahead of runner C. Each runner travels entire distance at a constant speed. What was the length of the race?

A. 36m
B. 48m
C. 60m
D. 72m
E. 84m
[Reveal] Spoiler: OA

_________________

My dad once said to me: Son, nothing succeeds like success.

Manager
Manager
User avatar
Joined: 14 Mar 2011
Posts: 203
Followers: 6

Kudos [?]: 123 [0], given: 21

Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 19 Sep 2011, 10:34
Let distance of race be x mtrs. Then when A finishes x m , B has run (x- 12)mtrs and C has run x-18 mtrs. so at this point B is 6 m ahead of C. Now to finish race b needs to run another 12 m, so he runs another 12 m. when B finishes race he is 8 m ahead of C. so last 12 m B has run, C has run 10 m.

as speeds are constant, we have equation,

x-12/ x-18 = 12/10 > x = 48.

Answer B
Manager
Manager
avatar
Status: Essaying
Joined: 27 May 2010
Posts: 150
Location: Ghana
Concentration: Finance, Finance
Schools: Cambridge
GMAT 1: 690 Q47 V37
GPA: 3.9
WE: Accounting (Education)
Followers: 1

Kudos [?]: 9 [0], given: 8

GMAT ToolKit User
Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 20 Sep 2011, 03:12
Can someone better explain this?
Expert Post
9 KUDOS received
Veritas Prep GMAT Instructor
User avatar
S
Joined: 16 Oct 2010
Posts: 7377
Location: Pune, India
Followers: 2288

Kudos [?]: 15134 [9] , given: 224

Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 20 Sep 2011, 03:34
9
This post received
KUDOS
Expert's post
6
This post was
BOOKMARKED
jamifahad wrote:
Three runners A,B and C run a race, with runner A finishing 12m ahead of runner B and 18m ahead of runner C, while runner B finishes 8m ahead of runner C. Each runner travels entire distance at a constant speed. What was the length of the race?

A. 36m
B. 48m
C. 60m
D. 72m
E. 84m


See if you can logically deduce the answer:
This is what happens in the race.

..._________C___(6)___B_______(12)________A (Finishing Point)

..._____________________C_______(8)______B (Finishing Point)

Focus on B and C.
B and C had a distance of 6 m between them. When B finished the race by covering another 12 m, he created a gap of 8 m between them i.e. he created another 2 m gap while running 12 m.
Since he created a gap of 2 m by running 12 m, he must have created a gap of 8 m by running a total of 12*4 = 48 m
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Math Forum Moderator
avatar
Joined: 20 Dec 2010
Posts: 2013
Followers: 163

Kudos [?]: 1827 [0], given: 376

Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 20 Sep 2011, 03:42
jamifahad wrote:
Three runners A,B and C run a race, with runner A finishing 12m ahead of runner B and 18m ahead of runner C, while runner B finishes 8m ahead of runner C. Each runner travels entire distance at a constant speed. What was the length of the race?

A. 36m
B. 48m
C. 60m
D. 72m
E. 84m



|---------------------------L-------------------|L=Length of the track
|-----------------------------C------B----------|A
|------------------------------------|<--12---->| A finishes 12 m ahead of B
|-----------------------------|<------18------->| A finishes 18 m ahead of C
|-----------------------------|<-6->|---------->| So, B was 6 meters ahead of C when A finished the race ------------1

|----------------------------------------C------|B
|----------------------------------------|<-8-->| B finishes 8 meter ahead of C--------------2


From 1 and 2, we can deduce that
B ran a distance of "L-12" meters taking a lead of 6 meters on C.

L-12->6
1 meter-> 6/(L-12) {:This is the per meter lead by B on C}

For the entire race of L meters, the lead would be
L meters->L*6/(L-12)

And we know the final lead was 8 meters
So,

6L/(L-12)=8
3L/(L-12)=4
3L=4L-48
L=48m

Ans: "B"
_________________

~fluke

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
avatar
Status: Do till 740 :)
Joined: 13 Jun 2011
Posts: 110
Concentration: Strategy, General Management
GMAT 1: 460 Q35 V20
GPA: 3.6
WE: Consulting (Computer Software)
Followers: 1

Kudos [?]: 13 [0], given: 19

GMAT ToolKit User
Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 13 Oct 2011, 10:53
Karishma,

can you pls xplain this part

Quote:
Since he created a gap of 2 m by running 12 m, he must have created a gap of 8 m by running a total of 12*4 = 48 m


Im nt able to logically deduce how we got the length of the race?

c ----b -----A(finishes)
Expert Post
3 KUDOS received
Veritas Prep GMAT Instructor
User avatar
S
Joined: 16 Oct 2010
Posts: 7377
Location: Pune, India
Followers: 2288

Kudos [?]: 15134 [3] , given: 224

Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 14 Oct 2011, 07:09
3
This post received
KUDOS
Expert's post
shankar245 wrote:
Karishma,

can you pls xplain this part

Quote:
Since he created a gap of 2 m by running 12 m, he must have created a gap of 8 m by running a total of 12*4 = 48 m


Im nt able to logically deduce how we got the length of the race?

c ----b -----A(finishes)



Think of the logic this way:

There are 2 people P and Q.
They both start running simultaneously at different but uniform speeds.
In the time P has covered 2 m, Q has covered only 1 m. What will be the distance between them by the time P covers a total of 4 m? P and Q are running at uniform speeds. Since P created a gap of 1 m in every 2 m he ran, the gap between them must be 2 m now.

Now imagine that P is standing ahead of Q by 6 m. They both start running. What happens by the time P covers 2 m? What is the gap between them? It must be 7 m now since another 1 m gap would have got created.

The logic used here is exactly the same.

B and C had a distance of 6 m between them at one point in time. B covered another 12 m and now the distance between them is 8 m. So basically a gap of 2 m was created by B when he ran 12 m. Overall, at the end of the race, the gap between B and C is 8 m. How much must B have run to create a gap of 8 m ( = 4*2)? He must have run 4*12 = 48 m
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 15486
Followers: 651

Kudos [?]: 210 [0], given: 0

Premium Member
Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 31 Oct 2014, 03:02
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Director
Director
avatar
S
Joined: 07 Dec 2014
Posts: 672
Followers: 3

Kudos [?]: 139 [0], given: 3

Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 06 Nov 2015, 22:54
Let d=distance of race.
Between A's finish and B's finish, B runs 12 meters while C runs 10 meters.
B's rate to C's rate=6/5.
When B finishes, he is 8 meters ahead of C.
6/5=d/(d-8)
d=48 meters
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 15486
Followers: 651

Kudos [?]: 210 [0], given: 0

Premium Member
Re: Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 21 Dec 2016, 03:16
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Director
Director
User avatar
G
Joined: 05 Mar 2015
Posts: 909
Followers: 9

Kudos [?]: 200 [0], given: 40

Three runners A, B and C run a race, with runner A finishing 12m ahead [#permalink]

Show Tags

New post 23 Dec 2016, 12:43
jamifahad wrote:
Three runners A, B and C run a race, with runner A finishing 12m ahead of runner B and 18m ahead of runner C, while runner B finishes 8m ahead of runner C. Each runner travels entire distance at a constant speed. What was the length of the race?

A. 36m
B. 48m
C. 60m
D. 72m
E. 84m


Although solution by karishma is more logical and faster approach
i providing one conceptual way for solving...

Let speed of A,B,C be A,B &C respectively
& total distance be D

then for the first case when A finishes,, the time run by all three will be same
D/A=(D-12)/B &&
D/A=(D-18)/C
or (D-12)/B=(D-18)/C----------(i)

again for second case when B finishes,, time taken by B & C will be same
thus D/B=(D-8)/C
C={(D-8)*B}/D-------(ii)

putting value of C from (ii) to (i) and solving for D we get
D=48

Ans B
Three runners A, B and C run a race, with runner A finishing 12m ahead   [#permalink] 23 Dec 2016, 12:43
    Similar topics Author Replies Last post
Similar
Topics:
A foot race had 36 teams of a dozen runners each. By noon nguyendinhtuong 1 09 Apr 2017, 19:18
2 Experts publish their posts in the topic It takes Davis x hours to complete the Road Runners Holiday Road Race Bunuel 4 25 Mar 2017, 13:04
2 Experts publish their posts in the topic Over the course of 8 races, a runner's finishing time was 5 seconds Bunuel 3 21 Feb 2017, 07:09
3 Experts publish their posts in the topic Jack and Jill are marathon runners. Jack can finish a marathon (42 km) Bunuel 5 09 Apr 2016, 14:26
9 Experts publish their posts in the topic Three runners A, B and C run a race with A finishing 20m ahead of B cleetus 11 06 Jan 2017, 01:47
Display posts from previous: Sort by

Three runners A, B and C run a race, with runner A finishing 12m ahead

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


cron

GMAT Club MBA Forum Home| About| 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®.