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

It is currently 20 Mar 2019, 22:47

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

A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.

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

Hide Tags

 
Intern
Intern
avatar
Joined: 28 Mar 2011
Posts: 2
A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post 24 Apr 2011, 11:44
2
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

50% (02:35) correct 50% (02:09) wrong based on 8 sessions

HideShow timer Statistics

A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.while another train Y starts from Ghaziabad at 4 p.m. and reaches Meerut at 5:30 p.m. The two trains will cross each other at:

A. 4:36 p.m.
B. 4:42 p.m.
C. 4:48 p.m.
D. 4:50 p.m.
E. 4:52 p.m.
Manager
Manager
User avatar
Joined: 07 Oct 2010
Posts: 139
Re: A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post Updated on: 24 Apr 2011, 13:34
We know that S = D/t , also D is fixed
Therefore, for train running from meerut to gazi… Sa = D / ta
but ta = 1 hr , therefore Sa = D
Now, for train running from Gazi… to meerut … Sb = D / tb
But tb = 1 ½ hr = 3/2 hr Therefore, Sb = 2D/3
However, D = Sa therefore Sb = 2Sa/3

Now, to calculate the time at which the trains will meet we need to calculate relative speed
Since, the trains are moving towards each other ,
Relative speed = Sa + Sb = Sa + 2Sa/3 = 5Sa /3
Distance will be “D” because it is fixed
And therefore Time at which the trains will meet i.e t = D / (5Sa /3)
but D = Sa therefore t = Sa / (5Sa /3) = 3 / 5 Hr = 3/5 * 60 = 36min

Thus, trains will meet at 4:36

Originally posted by vyassaptarashi on 24 Apr 2011, 12:16.
Last edited by vyassaptarashi on 24 Apr 2011, 13:34, edited 1 time in total.
Retired Moderator
avatar
Joined: 20 Dec 2010
Posts: 1790
Re: A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post 24 Apr 2011, 12:35
tparanidharan wrote:
A train X starts from Meerut at 4 P.M. and reaches Ghaziabad at 5 P.M. while
another train Y starts from Ghaziabad at 4 P.M. and reaches Meerut, at 5.30 PM. At what time the two trains meet each other.
.


Sol:

Let the distance between two points be "D miles"

Speed of X = D/1= D miles/h
Speed of Y = D/1.5= 2D/3 miles/h

Suppose X meets Y after completing "x miles" traveling for \(t_x\) hours and y traveled \(t_y\) hours

\(t_x=t_y\)

\(time=\frac{Distance}{Speed}\)

\(\frac{x}{D}=\frac{3(D-x)}{2D}\)

\(2x=3(D-x)\)

\(5x=3D\)

\(x=\frac{3}{5}D\)

Now,
x travels D miles in 1 hour
To travel (3/5)D miles, it would need 3/5 hours = 36minutes.

Thus; the trains meet at 4:36PM.
_________________

~fluke

GMAT Club Premium Membership - big benefits and savings

Veritas Prep GMAT Instructor
User avatar
D
Joined: 16 Oct 2010
Posts: 8997
Location: Pune, India
Re: A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post 24 Apr 2011, 16:32
2
tparanidharan wrote:
A train X starts from Meerut at 4 P.M. and reaches Ghaziabad at 5 P.M. while
another train Y starts from Ghaziabad at 4 P.M. and reaches Meerut, at 5.30 PM. At what time the two trains meet each other.
.


Great solutions above. Let us look at a solution without equations too.
X takes 1 hr to cover the distance that Y covers in 1.5 hrs. That is a ratio of 2:3.
So the ratio of their speeds is 3:2 since the distance they cover is the same.
Now imagine the situation when they meet. They start at 4 and meet after some time. In this time, they have covered distance in the ratio 3:2 since their speed is in the ratio 3:2.
Attachment:
Ques2.jpg
Ques2.jpg [ 3.53 KiB | Viewed 24874 times ]


Think of X now. It has covered 3/5th of the distance that it is supposed to cover to G. It needs to cover another 2/5th. So out of its 1 hr journey, it has covered 3/5th ie. 36 mins journey (because 3/5 * 60 min = 36 min)
So they met at 4:36.

Check out this detailed concept at
http://www.veritasprep.com/blog/2011/03 ... of-ratios/
http://www.veritasprep.com/blog/2011/03 ... os-in-tsd/
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

Intern
Intern
User avatar
Joined: 29 Mar 2011
Posts: 48
Location: Sweden
Concentration: Strategy, Finance
GMAT 1: 760 Q49 V47
GPA: 3.65
WE: Sales (Insurance)
A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post 08 May 2011, 04:59
Going to explain how I calculated it.

The first train travels the entire distance in 1 hour. The other train travels only 2/3 of the distance in one hour. When the trains meet they will together have covered the entire distance, from each others ends. The speeds of the trains are 1 times the distance per hours and 2/3 of the distance per hour. After traveling at their respective speeds for time X both trains will together have covered the entire distance.

Therefore:

1X + (2/3)X = 1.

(5/3)X = 1

X = 1/(5/3)

X = 3/5

Both trains will meet after 3/5 hours, as they will have covered the entire distance together at this point in time. 1/5 of an hour is 12 minutes. 12 x 3 is 36. The trains will meet at 4:36.
_________________

04/2011 GMATprep2: 710
05/07/2011 GMATprep1: 770
05/27/2011 GMAT test 1: 760

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 10153
Premium Member
Re: A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.  [#permalink]

Show Tags

New post 23 Dec 2018, 12:43
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 train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.   [#permalink] 23 Dec 2018, 12:43
Display posts from previous: Sort by

A train X starts from Meerut at 4 p.m. and reaches Ghaziabad at 5 p.m.

  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®.