GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 19 Feb 2019, 05:34

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 in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
  • Free GMAT Prep Hour

     February 20, 2019

     February 20, 2019

     08:00 PM EST

     09:00 PM EST

    Strategies and techniques for approaching featured GMAT topics. Wednesday, February 20th at 8 PM EST
  • Online GMAT boot camp for FREE

     February 21, 2019

     February 21, 2019

     10:00 PM PST

     11:00 PM PST

    Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.

A railroad worker finds himself trapped inside a tunnel at a point

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

Hide Tags

 
Intern
Intern
avatar
G
Joined: 01 Jan 2016
Posts: 28
A railroad worker finds himself trapped inside a tunnel at a point  [#permalink]

Show Tags

New post Updated on: 12 Sep 2017, 18:16
2
12
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

28% (02:49) correct 72% (03:24) wrong based on 95 sessions

HideShow timer Statistics

A railroad worker finds himself trapped inside a tunnel at a point that is 25% of the length of the tunnel with a train approaching towards the near end with constant speed. He calculates that if he runs towards the near end doubling his speed then he would just manage to save himself. If on the other hand, he reduced his speed by 25% and ran towards the far end of the tunnel, then he would also just manage to avert danger. What is the the ratio of the speed of the train to the speed of the worker?
(1) 8 : 7
(2) 7 : 8
(3) 3 : 1
(4) 2 : 1
(5) None of these

Originally posted by jake092 on 12 Sep 2017, 09:51.
Last edited by jake092 on 12 Sep 2017, 18:16, edited 1 time in total.
Intern
Intern
avatar
B
Joined: 29 Dec 2016
Posts: 1
Re: A railroad worker finds himself trapped inside a tunnel at a point  [#permalink]

Show Tags

New post 12 Sep 2017, 10:31
1
Let length of tunnel be - x
Let distance of train from nearest end be - y
Let speed of man be - m
Let speed of train be - t

Condition 1 : when the man runs to the nearest end of tunnel
To be just in time we can write the equation as

y/t = [25x]/[100*(2m)]
or y = xt/8m ..........eq (1)

Condition 2 : When the man runs to the further end of the tunnel
To be just in time we can write the equation as

(y+x)/t = [75x/100]/[75m/100]

On simplifing we get

y = (xt/m) - x .........(eq 2)

equating eq 1 and eq 2 we get

xt/8m = (xt/m) - x
simpliying we get

t/m = 8/7

Hence answer is A
VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1156
Re: A railroad worker finds himself trapped inside a tunnel at a point  [#permalink]

Show Tags

New post 12 Sep 2017, 10:33
theperfectgentleman wrote:
A railroad worker finds himself trapped inside a tunnel at a point that is 25% of the length of the tunnel with a train approaching towards the near end with constant speed. He calculates that if he runs towards the near end doubling his speed then he would just manage to save himself. If on the other hand, he reduced his speed by 25% and ran
towards the far end of the tunnel, then he would also just manage to avert danger. What is the the ratio of the speed of the train to the speed of the worker?
(1) 8 : 7
(2) 7 : 8
(3) 3 : 1
(4) 2 : 1
(5) None of these


rt=rate of train
rw=rate of worker
d=distance from engine to tunnel
t=distance of tunnel
equation1: d/rt=(t/4)/2rw➡
rt/rw=8d/t
equation2: (d+t)/rt=(3t/4)/(3rw/4)➡
rt/rw=t+d/t
8d/t=(t+d)/t➡
8d=t+d➡
t=7d
rt/rw=t+d/t=8d/7d=8:7
(1)
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9845
Premium Member
Re: A railroad worker finds himself trapped inside a tunnel at a point  [#permalink]

Show Tags

New post 20 Oct 2018, 03:00
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

GMAT Club Bot
Re: A railroad worker finds himself trapped inside a tunnel at a point   [#permalink] 20 Oct 2018, 03:00
Display posts from previous: Sort by

A railroad worker finds himself trapped inside a tunnel at a point

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.