The ‘moving walkway’ is a 300-foot long walkway consisting : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 23 Jan 2017, 08:59

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

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

The ‘moving walkway’ is a 300-foot long walkway consisting

Author Message
TAGS:

Hide Tags

Intern
Joined: 12 Nov 2009
Posts: 46
Followers: 0

Kudos [?]: 18 [1] , given: 2

The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

02 Dec 2009, 19:34
1
KUDOS
14
This post was
BOOKMARKED
00:00

Difficulty:

85% (hard)

Question Stats:

53% (02:48) correct 47% (01:42) wrong based on 621 sessions

HideShow timer Statistics

The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

A. 2 feet per second
B. 2.5 feet per second
C. 3 feet per second
D. 4 feet per second
E. 5 feet per second
[Reveal] Spoiler: OA

Last edited by Bunuel on 07 May 2012, 04:12, edited 1 time in total.
Senior Manager
Joined: 30 Aug 2009
Posts: 286
Location: India
Concentration: General Management
Followers: 3

Kudos [?]: 163 [1] , given: 5

Re: Question from Manhattan CAT [#permalink]

Show Tags

02 Dec 2009, 22:35
1
KUDOS
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

3.75feet per second?

total distance is 300 feets
120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
remaining 180 feet is covered at a speed of (Bills' speed + Belt Speed) = (0+3) = 3feet/sec. Time taken 60sec

so total time taken to cover 300 foot long walkway is 80 sec. Avg Speed = 300/80 = 3.75 feet/sec
Intern
Joined: 25 Nov 2009
Posts: 30
Followers: 0

Kudos [?]: 16 [11] , given: 4

Re: Question from Manhattan CAT [#permalink]

Show Tags

03 Dec 2009, 01:11
11
KUDOS
2
This post was
BOOKMARKED
Here's what I think the answer should be
-------

Time Bill takes to catchup with group = 120/3
= 40 secs
Time Group has moved in 40 secs = 40 x 3
= 120 feet
Remaining Distance on walkway = 300 - 120 -120
= 60
Time taken to cover the last 60 ft = 60/3
= 20sec

Total time Bill spends on walkway = 40 + 20 = 60 secs
Total length of walkway = 300 feet

Bill's Average speed = 300/60 = 5 ft/sec

Last edited by prome2 on 03 Dec 2009, 01:31, edited 1 time in total.
Intern
Joined: 25 Nov 2009
Posts: 30
Followers: 0

Kudos [?]: 16 [1] , given: 4

Re: Question from Manhattan CAT [#permalink]

Show Tags

03 Dec 2009, 01:25
1
KUDOS
kp1811 wrote:
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

3.75feet per second?

total distance is 300 feets
120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
remaining 180 feet is covered at a speed of (Bills' speed + Belt Speed) = (0+3) = 3feet/sec. Time taken 60sec

so total time taken to cover 300 foot long walkway is 80 sec. Avg Speed = 300/80 = 3.75 feet/sec

I could be wrong, but the average of 2 average speeds is not the average speed of the entire journey.

Let's take a man cycling 60 miles to work, at 10 miles/hour there and 15 miles/hour back.
The average of the two average speeds will be 12.5 miles/hour

However, the computed average speed is total dist over total time.
If he cycles 10 miles/hour there, he will take 6 hours, and at 15 miles/hour back he will take 4 hours.

120miles/10 hours = 12 miles/hour

----

Although I believe weighted average could be used to compute average speed.
But you would need to know time travelled at each speed.

((AverageSpeed1*Time@Speed1) + (AverageSpeed2*Time@Speed2) / (TotalTime)
=((6*10)+(4*15)) / 10
Senior Manager
Joined: 30 Aug 2009
Posts: 286
Location: India
Concentration: General Management
Followers: 3

Kudos [?]: 163 [0], given: 5

Re: Question from Manhattan CAT [#permalink]

Show Tags

03 Dec 2009, 03:40
kp1811 wrote:
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

3.75feet per second?

total distance is 300 feets
120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
remaining 180 feet is covered at a speed of (Bills' speed + Belt Speed) = (0+3) = 3feet/sec. Time taken 60sec

so total time taken to cover 300 foot long walkway is 80 sec. Avg Speed = 300/80 = 3.75 feet/sec

120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
but in this 20sec the group moves a further of 20*3= 60feet so Bill will take another 60/6 =10sec to catch the group. Now remaining 120 feet will be covered in 120/3 = 40 sec. So total time to cover is 20+10+40 = 70sec
Avg speed = 300/70 = 30/7 feet/sec
Manager
Joined: 07 Jul 2009
Posts: 230
Followers: 3

Kudos [?]: 99 [0], given: 13

Re: Question from Manhattan CAT [#permalink]

Show Tags

03 Dec 2009, 07:14
prome2 wrote:
Here's what I think the answer should be
-------

Time Bill takes to catchup with group = 120/3
= 40 secs
Time Group has moved in 40 secs = 40 x 3
= 120 feet
Remaining Distance on walkway = 300 - 120 -120
= 60
Time taken to cover the last 60 ft = 60/3
= 20sec

Total time Bill spends on walkway = 40 + 20 = 60 secs
Total length of walkway = 300 feet

Bill's Average speed = 300/60 = 5 ft/sec

This is correct. Average speed is total distance/total time.
Manager
Joined: 02 Jun 2011
Posts: 159
Followers: 1

Kudos [?]: 75 [0], given: 11

Re: Question from Manhattan CAT [#permalink]

Show Tags

07 May 2012, 01:06
kp1811 wrote:
kp1811 wrote:
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

3.75feet per second?

total distance is 300 feets
120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
remaining 180 feet is covered at a speed of (Bills' speed + Belt Speed) = (0+3) = 3feet/sec. Time taken 60sec

so total time taken to cover 300 foot long walkway is 80 sec. Avg Speed = 300/80 = 3.75 feet/sec

120 feet is covered at a speed of (Bills' speed + Belt Speed) = (3+3) = 6feet/sec. Time taken 20sec
but in this 20sec the group moves a further of 20*3= 60feet so Bill will take another 60/6 =10sec to catch the group. Now remaining 120 feet will be covered in 120/3 = 40 sec. So total time to cover is 20+10+40 = 70sec
Avg speed = 300/70 = 30/7 feet/sec

is this correct? does the group move further, even so is it required to be calculated for bill?
Manager
Joined: 21 Feb 2012
Posts: 116
Location: India
Concentration: Finance, General Management
GMAT 1: 600 Q49 V23
GPA: 3.8
WE: Information Technology (Computer Software)
Followers: 1

Kudos [?]: 119 [0], given: 15

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

09 May 2012, 10:36
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

A. 2 feet per second
B. 2.5 feet per second
C. 3 feet per second
D. 4 feet per second
E. 5 feet per second

Hi Bunuel, could u please explain how to solve this question...
Manager
Joined: 26 Mar 2012
Posts: 59
Concentration: Social Entrepreneurship, Strategy
Schools: LBS '16 (M)
GMAT 1: 710 Q47 V40
GPA: 3.7
Followers: 1

Kudos [?]: 33 [11] , given: 3

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

30 May 2012, 18:24
11
KUDOS
2
This post was
BOOKMARKED
This is how I broke it down:

Total Distance = 300 feet
default rate is 3fps (feet per second)
walking rate is 6fps (default + walking)
catch up rate: is walking rate - default rate = 6-3 = 3fps

Part 1: Time for Catch up
As he gets on the walk way he instantly starts "catching up" to the group that is 120 feet ahead of him. How long does this take?

D/R = Time; so 120feet/3fps [ note I'm using the catch up rate here ] = 40 seconds of catch up

After 40 seconds, how much of the 300 feet of the moonwalk has been used? well if he was moving for 40 seconds at 6 feet per second (he was walking) then he covered 240 feet of actual walkway.

300-240 feet = 60 feet.

There are only 60 feet left of walkway.

Part 2: Standing with the crowd
Now bill just idles with the crowd for the last 60 feet. 60ft/3fps [ note this is the default rate ] = 20 seconds.

Part 3: Average rate

6 fps for 40 seconds = 240 feet
3 fps for 20 seconds = 60 feet
X fps for 60 seconds = 300 feet

300/60 = 5fps average rate. Answer is E.
_________________

That 700.. I can taste it

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13517
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

20 Sep 2013, 10:21
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.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 36614
Followers: 7099

Kudos [?]: 93533 [0], given: 10578

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

20 Sep 2013, 10:29
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

A. 2 feet per second
B. 2.5 feet per second
C. 3 feet per second
D. 4 feet per second
E. 5 feet per second

Similar question to practice: barry-walks-from-one-end-to-the-other-of-a-30-meter-long-141013.html
_________________
Intern
Joined: 05 Jun 2011
Posts: 15
Schools: Kellog, Stern, Stanford, Booth,HBS, Wharton
Followers: 0

Kudos [?]: 13 [3] , given: 36

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

26 Sep 2013, 09:29
3
KUDOS
1
This post was
BOOKMARKED
I agree with the above posters about the way to handle the equations (Catona & Prome2) but to me there is an option that hasn't been discussed that just POPS out at me. I don't know if it does for anyone else...

If you look at the options for the choices:

A. 2 feet per second
B. 2.5 feet per second
C. 3 feet per second
D. 4 feet per second
E. 5 feet per second

A, B, and C don't make ANY sense! we know for some time...(a majority of the 300ft) Bill will walk at a pace of 6ft per second...and then at some later time he will stop and move at 3 ft per second... The average MUST be between 3-6 ft per second or the Earth is FLAT!!!.

So we are down to D & E, D doesn't make sense on a weighted averages level because we know when Bill gets on the walkway the patrons are already 40% of the way down the 300ft walkway AND they are still moving at half the rate of Bill!! So for Bill to average 4 ft per second he would have had to spend a majority of the 300 ft at 3ft per second because 4 is much closer (when you factor in the size of the values we're dealing with 2 is double 1) to 3 than to 6. We know from the information that isn't possible. Bill must have spent the majority of his time at 6 ft per second before he stopped walking. That leaves only answer E as plausible.
Manager
Joined: 26 Feb 2012
Posts: 116
Location: India
Concentration: General Management, Finance
WE: Engineering (Telecommunications)
Followers: 0

Kudos [?]: 19 [0], given: 56

Re: Question from Manhattan CAT [#permalink]

Show Tags

22 Feb 2014, 01:20
prome2 wrote:
Here's what I think the answer should be
-------

Time Bill takes to catchup with group = 120/3
= 40 secs
Time Group has moved in 40 secs = 40 x 3
= 120 feet......Please make me understand whether bill there in this group to cover 120 feet.......
Remaining Distance on walkway = 300 - 120 -120
= 60
Time taken to cover the last 60 ft = 60/3
= 20sec

Total time Bill spends on walkway = 40 + 20 = 60 secs
Total length of walkway = 300 feet

Bill's Average speed = 300/60 = 5 ft/sec

I was little confused please som1 help me out
Math Expert
Joined: 02 Sep 2009
Posts: 36614
Followers: 7099

Kudos [?]: 93533 [0], given: 10578

Re: Question from Manhattan CAT [#permalink]

Show Tags

22 Feb 2014, 02:04
Expert's post
2
This post was
BOOKMARKED
prasannajeet wrote:
prome2 wrote:
Here's what I think the answer should be
-------

Time Bill takes to catchup with group = 120/3
= 40 secs
Time Group has moved in 40 secs = 40 x 3
= 120 feet......Please make me understand whether bill there in this group to cover 120 feet.......
Remaining Distance on walkway = 300 - 120 -120
= 60
Time taken to cover the last 60 ft = 60/3
= 20sec

Total time Bill spends on walkway = 40 + 20 = 60 secs
Total length of walkway = 300 feet

Bill's Average speed = 300/60 = 5 ft/sec

I was little confused please som1 help me out

No, he is not. Bill takes 40 seconds to catch up the group but in that time the walkway continues to move at 3 feet per second, thus the group (as well as Bill) moves 3*40=120 feet towards the end.

Hope it's clear.
_________________
Intern
Joined: 01 Sep 2013
Posts: 1
Followers: 0

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

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

27 Feb 2014, 13:00
Hello,
I just bumped into this question, I solved it this way :
At time t, Bill meets the crowd at the the distance x, the crowd has covered 120+X :
=> X/6=(X+120)/3
=> X=720/3=240 feet (I neglected the sign '-', x being a distance, so an absolute value)
So, Bill spends 240/6 =40 sec to cover the 240 feet

Remain 60 feet that bills covers in : 60/3 = 20 s

Hence total time : 40+20=60 sec.t

Bill s rate is : 300/60 = 5 feet

I think there s sthg wrong with my reasoning but I cant figure it out
Thank you for helping
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 47

Kudos [?]: 1937 [0], given: 193

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

28 Feb 2014, 01:52
First 240 Feet are covered @ 6 f/sec...... so time taken = 40sec
Last 60 Feet are covered @ 3 f/sec...... so time taken = 20sec

Total time = 60seconds, total distance = 300 Feets

Avg speed = 300/60 = 5 = Answer = E
_________________

Kindly press "+1 Kudos" to appreciate

Math Expert
Joined: 02 Sep 2009
Posts: 36614
Followers: 7099

Kudos [?]: 93533 [0], given: 10578

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

28 Feb 2014, 02:44
breakfree1 wrote:
Hello,
I just bumped into this question, I solved it this way :
At time t, Bill meets the crowd at the the distance x, the crowd has covered 120+X :
=> X/6=(X+120)/3
=> X=720/3=240 feet (I neglected the sign '-', x being a distance, so an absolute value)
So, Bill spends 240/6 =40 sec to cover the 240 feet

Remain 60 feet that bills covers in : 60/3 = 20 s

Hence total time : 40+20=60 sec.t

Bill s rate is : 300/60 = 5 feet

I think there s sthg wrong with my reasoning but I cant figure it out
Thank you for helping

The equation should be $$\frac{x}{6}=\frac{(x-120)}{3}$$ --> $$x=240$$.

Hope it helps.
_________________
Manager
Joined: 05 Jun 2012
Posts: 130
Schools: IIMA
Followers: 1

Kudos [?]: 13 [0], given: 66

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

16 Apr 2014, 07:49
I think all info should be one place ; so here goes

let x be total distance covered by Bill till he catches group of people

as we know speed=distance/time; as time will be equal when it will catch

x/6(relative speed bill +group)=total -120/3 (*obviously it will be added only then bill will be able to catch; total x but 120 is already covered)

x/6=x-120/3

x=240 covered by speed of 6 , so time took 240/6=40, rest 60 will be covered by 3 (*speed of wheel)=60/3=20

Avg. speed of bill= 300/(40+20)=5
_________________

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

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13517
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

28 May 2015, 18:23
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.
_________________
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7130
Location: Pune, India
Followers: 2140

Kudos [?]: 13705 [2] , given: 222

Re: The ‘moving walkway’ is a 300-foot long walkway consisting [#permalink]

Show Tags

28 May 2015, 19:20
2
KUDOS
Expert's post
Gmatter111 wrote:
The ‘moving walkway’ is a 300-foot long walkway consisting of a conveyor belt that moves continuously at 3 feet per second. When Bill steps on the walkway, a group of people that are also on the walkway stands 120 feet in front of him. He walks toward the group at a rate of 3 feet per second. Once Bill reaches the group of people, he stops walking and stands with them until the walkway ends. What is Bill’s average rate of movement for his trip along the moving walkway?

A. 2 feet per second
B. 2.5 feet per second
C. 3 feet per second
D. 4 feet per second
E. 5 feet per second

Using relative speed concepts:

Bill covers 120 feet at a relative speed of 6 - 3 = 3 feet/sec. Time taken to cover 120 feet = 120/3 = 40 sec
Distance covered in 40 secs = 6*40 = 240 feet
So now he just has 300 - 240 = 60 feet leftover to cover at 3 feet/sec
Time taken to cover 60 feet = 60/3 = 20 sec

Average Speed = Total Distance/Total Time = 300/(40 + 20) = 5 feet/sec

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

Re: The ‘moving walkway’ is a 300-foot long walkway consisting   [#permalink] 28 May 2015, 19:20

Go to page    1   2    Next  [ 24 posts ]

Similar topics Replies Last post
Similar
Topics:
2 The figure above represents a rectangular garden with a walkway around 4 11 May 2015, 07:19
A square garden is surrounded by a 2 feet wide walkway on 2 26 Jul 2012, 04:34
3 Long-trem members to retire 4 03 Jul 2011, 03:14
20 In a game of chess the moves of whites and blacks alternate 6 23 Feb 2008, 07:08
7 The moving walkway is a 300-foot long conveyor belt that 6 02 Aug 2007, 16:08
Display posts from previous: Sort by