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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

09 Jul 2012, 03:42

9

This post received KUDOS

26

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

95% (hard)

Question Stats:

44% (03:00) correct
56% (02:06) wrong based on 670 sessions

HideShow timer Statistics

In racing over a given distance d at uniform speed, A can beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line B is 8 yards ahead of C, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

09 Jul 2012, 07:14

7

This post received KUDOS

Bunuel wrote:

carcass wrote:

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Answer: C.

Hope it's clear.

Hi Can we also resolve by comparing time taken, i.e. d/a=(d-20)/b d/b=(d-10)/c d/a=(d-28)/c

we can resolve d=100 from these eqn.. _________________

Best Vaibhav

If you found my contribution helpful, please click the +1 Kudos button on the left, Thanks

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

20 Jul 2012, 20:39

I want to ask bunnel how did he get this " 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards.." can you pls explain a bit in detail. thanks

I want to ask bunnel how did he get this " 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards.." can you pls explain a bit in detail. thanks

Consider the case when A, B and C are racing each other. When A is on the finish line B must be 20 yards from the finish line and C must be 28 yards from the finish line. Hence when B is 20 yards from the finish line he's 28-20=8 yards ahead of C.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

24 Jul 2012, 00:58

Bunuel wrote:

carcass wrote:

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Answer: C.

Hope it's clear.

Hi Bunnel,

Can you please explain this part?

since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards. _________________

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

27 Jun 2013, 17:50

11

This post received KUDOS

3

This post was BOOKMARKED

1. When A touches d, B is at d-20 and C is at d-28 2. When B completes d, C completes d-10 3. Equate d-20 / d-28 = d / d-10 because the ratio of the speed of B to the speed of C is a constant. 4. d= 100 _________________

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

04 Jul 2013, 10:44

2

This post received KUDOS

1

This post was BOOKMARKED

Think it into a other way. 1) When A completes, B is 20 Behind and C is 28 Behind. C is 8 behind B. 2) When B completes, C is 10 Behind.

What it refers is that in last 20 yards B has gained 2 yards, which refers that B is gaining 1 yard over C in every 10 yard it covers, so in last 80 yards it has gained 8 yards, so total is 80+20 = 100 :D

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

03 Aug 2013, 12:16

2

This post received KUDOS

1

This post was BOOKMARKED

In racing over a given distance d at uniform speed, A can beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

We are given nothing about time and nothing about rate. Solving using a traditional formula (i.e. distance = rate*time) might be difficult. Is that correct?

A must be 28 yards ahead of C. We know that A beats both B and C.

When A hits the finish line, it is 20 yards ahead of B and 28 yards ahead of C. This means at this time B is 8 yards ahead of C but it beats C by 10 yards. In 20 yards, it has to gain a two further yards between itself and C. Because A, B, C travel at a constant rate, B gains on C by 2 yards every 20 yards. This means that when B and C started out they were even and after 20 yards B was two ahead of C, after 40 yards B was 4 ahead of C, etc. B would have to travel 100 yards for it to gain 10 yards on C.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

16 Aug 2013, 03:13

2

This post received KUDOS

Another method to solve such questions : Let us consider the case when all three are racing each other. A is ahead of B by 20 yards at the finish and ahead of c by 28 yards, which means B is ahead of C by 8 yards at that instant. Now B defeats C by 10 yards, means the duration during which B covered 20, C covered 8+10=18. Hence, the ratio of their speeds is 10:9. That means in a race of 10yards B defeats c by 1 yard , so to defeat him by 10 yards the race should be of 10x10 =100 yards.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

10 Jan 2014, 07:04

SravnaTestPrep wrote:

1. When A touches d, B is at d-20 and C is at d-28 2. When B completes d, C completes d-10 3. Equate d-20 / d-28 = d / d-10 because the ratio of the speed of B to the speed of C is a constant. 4. d= 100

Hi Sravna,

I dont follow how the ratio of the speeds are constant? what about the time factor while equating? as per the discussions in the various for this questions here it is re-iterated time and again that B gains 2 yards in the last 20 yards? if that is the case how can the speed ratios be constant?

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

18 Jan 2014, 23:47

rawjetraw wrote:

SravnaTestPrep wrote:

1. When A touches d, B is at d-20 and C is at d-28 2. When B completes d, C completes d-10 3. Equate d-20 / d-28 = d / d-10 because the ratio of the speed of B to the speed of C is a constant. 4. d= 100

Hi Sravna,

I dont follow how the ratio of the speeds are constant? what about the time factor while equating? as per the discussions in the various for this questions here it is re-iterated time and again that B gains 2 yards in the last 20 yards? if that is the case how can the speed ratios be constant?

please help. confused

Hi Bunuel,

could you please your insight on this solution? I haven't received a reply from Sravna. Thanks!

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

13 May 2014, 09:28

narangvaibhav wrote:

Bunuel wrote:

carcass wrote:

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Answer: C.

Hope it's clear.

Hi Can we also resolve by comparing time taken, i.e. d/a=(d-20)/b d/b=(d-10)/c d/a=(d-28)/c

we can resolve d=100 from these eqn..

You can'tresolve this..... 3equation and four variables....need one more equation here _________________

May everyone succeed in their endeavor. God Bless!!!

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

18 May 2014, 04:39

1

This post was BOOKMARKED

rawjetraw wrote:

rawjetraw wrote:

SravnaTestPrep wrote:

1. When A touches d, B is at d-20 and C is at d-28 2. When B completes d, C completes d-10 3. Equate d-20 / d-28 = d / d-10 because the ratio of the speed of B to the speed of C is a constant. 4. d= 100

Hi Sravna,

I dont follow how the ratio of the speeds are constant? what about the time factor while equating? as per the discussions in the various for this questions here it is re-iterated time and again that B gains 2 yards in the last 20 yards? if that is the case how can the speed ratios be constant?

please help. confused

Hi Bunuel,

could you please your insight on this solution? I haven't received a reply from Sravna. Thanks!

Lemme try and explain.

In a given times A runs d, B runs d-20, and C runs d-28. Since the time is same their speed a, b, c are in the ratio of the distance the travelled Thus a:b:c = d:d-20:d-28 Also, we know that b:c= d: d-10

Thus, equating b:c in both the cases, we get

d-20/d-28 = d/d-10

Solving this we get d= 100.

A more intuitive approach has been given by Bunuel in this tread. The approach works as the speeds are constant and are in direct proportion with the distance if time traveled is same.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

18 May 2014, 04:46

enders wrote:

narangvaibhav wrote:

Bunuel wrote:

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Answer: C.

Hope it's clear. Hi Can we also resolve by comparing time taken, i.e. d/a=(d-20)/b d/b=(d-10)/c d/a=(d-28)/c

we can resolve d=100 from these eqn..

You can'tresolve this..... 3equation and four variables....need one more equation here

You can resolve this very easily. Also, we don't need to find all the four variables. We can't find the speed of a, b and c individually as we don't know about the distance

The first one can be written as a/b = d/d-20 second one is b/c = d/d-10

Multiplying these two yeilds a/c = d^2/(d-10)(d-20)

Third one also says a/c = d/d-28

We equate these 2 and get the result as 100. A more intuitive way has been already discusses. You should use that way.

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

17 Jun 2014, 02:07

1

This post was BOOKMARKED

rawjetraw wrote:

SravnaTestPrep wrote:

1. When A touches d, B is at d-20 and C is at d-28 2. When B completes d, C completes d-10 3. Equate d-20 / d-28 = d / d-10 because the ratio of the speed of B to the speed of C is a constant. 4. d= 100

Hi Sravna,

I dont follow how the ratio of the speeds are constant? what about the time factor while equating? as per the discussions in the various for this questions here it is re-iterated time and again that B gains 2 yards in the last 20 yards? if that is the case how can the speed ratios be constant?

please help. confused

Hi,

Very sorry for such a late reply.

Let us say that B travels a distance x and in the same time C travels distance y. The ratio of the distance = x/y. This is also the ratio of their speed since time is the same.

In the actual problem we have this ratio as d-20/d-28. This gives the ratio of their speed.

Similarly when B reaches d, c reaches d-10. The time taken by both to reach the respective distance is the same. This d/d-10 also gives the ratio of the speed of B and C. Thus we can equate the two and find d. _________________

Re: In racing over a given distance d at uniform speed, A can be [#permalink]

Show Tags

18 Jun 2014, 06:27

Bunuel wrote:

carcass wrote:

In racing over a given distance d at uniform speed, A can be beat B by 20 yards, B can beat C by 10 yards, and A can beat C by 28 yards. Then d, in yards, equal

A. not determined by the give information B. 58 C. 100 D. 116 E. 120

Given: A can beat B by 20 yards, A can beat C by 28 yards, B can beat C by 10 yards,

So, when A is on the finish line B is 20 yards back and C is 28 yards back.

Hence, 20 yards before the finish line C is 8 yards ahead of B, and since the final difference between B and C is 10 yards, then B gains 2 yards every 20 yard. To gain the final difference of 10=2*5 yards B should run total of 20*5=100 yards.

Answer: C.

Hope it's clear.

Bunuel how can C be ahead of B unless I am missing something !!

gmatclubot

Re: In racing over a given distance d at uniform speed, A can be
[#permalink]
18 Jun 2014, 06:27

This is the kickoff for my 2016-2017 application season. After a summer of introspect and debate I have decided to relaunch my b-school application journey. Why would anyone want...

Sometimes Mom comes into town, you meet her at the airport to surprise her. Shenanigans ensue. You grab dinner and chat. You don’t write a long blog post that...