It is currently 27 Jun 2017, 05:40

### 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

# Trains are leaving station A for station B every 15 minutes

Author Message
TAGS:

### Hide Tags

Manager
Joined: 14 Jun 2008
Posts: 161
Trains are leaving station A for station B every 15 minutes [#permalink]

### Show Tags

26 Aug 2008, 09:43
2
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

83% (02:06) correct 17% (01:26) wrong based on 110 sessions

### HideShow timer Statistics

Trains are leaving station A for station B every 15 minutes starting 8:00 am. The distance between the stations is 80 km. If a train leaves station B for station A at 11:05 am, how many oncoming trains will it meet?

1. Trains from station A to station B travel at 40 kmh
2. The train from station B to station A travels at 40 kmh
Manager
Joined: 14 Jun 2008
Posts: 161

### Show Tags

26 Aug 2008, 09:44
i am having some doubts with the OA. will ask once someone has posted an answer.
Director
Joined: 12 Jul 2008
Posts: 515
Schools: Wharton

### Show Tags

26 Aug 2008, 10:06
1
KUDOS
sset009 wrote:
Trains are leaving station A for station B every 15 minutes starting 8:00 am. The distance between the stations is 80 km. If a train leaves station B for station A at 11:05 am, how many oncoming trains will it meet?

1. Trains from station A to station B travel at 40 kmh
2. The train from station B to station A travels at 40 kmh

I would go with C.

You need to know how many trains going from A to B are on the tracks 3 hours and 5 minutes after 8am. This requires you to know (1).

But that is not enough. You also need to know how many trains depart from station A in between 11:05 and the train's arrival at Station A. For this, you need to know how long the train takes to travel from B to A.
Manager
Joined: 14 Jun 2008
Posts: 161

### Show Tags

27 Aug 2008, 00:03
just a thought
since u know the speed of train leaving from B to A, and teh distrance, u know how long it will travel
so wont it just meet trains at 15 minute intervals irrespetive of how fast they travel?

do u really need the information of speed of train fro A to B?
Intern
Joined: 23 Feb 2006
Posts: 5

### Show Tags

27 Aug 2008, 01:32

You need to know speed of trains from A->B so that you can discard trains that have reached before 11.05
However this information alone is not sufficient as we need to know the speed of train from B->A. For example if this train is an express train traveling at 400km/h it would take less time to travel and hence meet fewer trains. However if this train is a slow coach traveling at 1km/hr it would meet a lot more trains. Both speeds are necessary.
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16001
Re: Trains are leaving station A for station B every 15 minutes [#permalink]

### Show Tags

29 May 2014, 02:51
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.
_________________
Intern
Joined: 11 Aug 2013
Posts: 26
Location: India
Concentration: Finance, General Management
GMAT 1: 620 Q47 V28
GPA: 3.23
WE: Information Technology (Investment Banking)
Re: Trains are leaving station A for station B every 15 minutes [#permalink]

### Show Tags

03 Jun 2014, 09:05
From (1) we get that train leaving from station A takes 2 hours to reach station B.
But We are not given the speed of the trains leaving station B.
Therefore Time taken for Train to reach from station A to B = ? . Not SUfficient
From (2) it's Exactly the opposite of Option (1). Hence Not Sufficient

Combining (1) and(2) we get the Time taken by train to travel from each side and hence no of Oncoming trains can be calculated. Sufficient

P.S: Since this is a DS question we don't have to get the exact number

Hope This Helps
_________________

Thanks
----------------
Click +1 Kudos if my post helped...

Intern
Joined: 03 Jul 2016
Posts: 1
Re: Trains are leaving station A for station B every 15 minutes [#permalink]

### Show Tags

03 Jul 2016, 08:43
Since train from station A which left left at 9 am reached st.B at 11
Therefore the train leaving leaving fr st.A at 9:15 will still be on its way to reaching St.B and will hit St.B at 11.15 in which it will encounter our train leaving St.B at 11
Therefore total trains crossing the train fr St B will be 16

Posted from my mobile device
Intern
Joined: 06 Nov 2016
Posts: 18
Re: Trains are leaving station A for station B every 15 minutes [#permalink]

### Show Tags

13 Jan 2017, 16:44
Distance of 80 kms between the trains. We would need to know the speed of both the trains to calculate the time it would take for each train to reach the destination.

1)Trains from station A to station B travel at 40 kmh
Each train takes D/T time to reach the destination. 80/40 km/h = 2 hours. So a train leaving station A at 8:00 am, would reach the destination at 10:00 pm. The other trains at 8:15,8:30, 8:45, 9:00 pm. However, we need to know the speed at which the train from station B travels to station A. This would determine the number of trains it would cross. No information on train B. Not Sufficient

2) The train from station B to station A travels at 40 kmh

Similar to the above case, we do not have any information on trains leaving from Station A. Hence, Not Sufficient.

Both together, we should be able to solve the problem.
Below trains would travel from Station A - Station B.
8:00 - 10:00am
8:15 - 10:15 am
8:30 - 10:30 am
8:45 - 10:45 am
9:00 - 11:00 am
9:15 - 11:15 am
9:30 - 11:30 am.
9:45 - 11:45 am
10:00 - 12:00 pm
10:15 - 12:15 pm
10:30 - 12:30 pm
10:45 - 12:45 pm
11:00 - 1:00 pm
11:15 - 1:15 pm
11:30 - 1:30 pm
11:45 - 1:45 pm
12:00 - 2:00 pm
12:15 - 2:15 pm
12:30 - 2:30 pm
12:45 - 2:45 pm.
1:00 - 3:00 pm .

From Station B to Station A, starting at 11:05, it would reach the destination at 1:05 am.

It would be 16 trains as shown above.
Re: Trains are leaving station A for station B every 15 minutes   [#permalink] 13 Jan 2017, 16:44
Similar topics Replies Last post
Similar
Topics:
3 Train A leaves the station at 5:00, and travels north at 50 miles per 2 19 May 2017, 01:31
6 A certain train traveled from Station A to Station B. Was the train's 3 15 Sep 2016, 03:52
31 A train traveled from Station A to Station B at an average speed of 80 8 05 Jul 2016, 00:50
11 Trains A and B left stations R and S simultaneously on two s 6 20 Aug 2015, 03:20
5 Station Q is to the East of Station T. At 12 noon, a train s 6 18 Feb 2016, 04:09
Display posts from previous: Sort by