Author 
Message 
Senior Manager
Joined: 22 Sep 2005
Posts: 276

Train T leaves from town A for town B and travels at a [#permalink]
Show Tags
15 Oct 2006, 12:59
Question Stats:
0% (00:00) correct
0% (00:00) wrong based on 1 sessions
HideShow timer Statistics
This topic is locked. If you want to discuss this question please repost it in the respective forum.
Train T leaves from town A for town B and travels at a constant speed of x mph. Train S leaves town B for town A, later than the train T, and also travels at a constant speed of y mph. Will they meet closer to A or to B?
1) y>x
2) They finished their trips at the same time



SVP
Joined: 05 Jul 2006
Posts: 1747

Train T leaves from town A for town B and travels at a constant speed of x mph. Train S leaves town B for town A, later than the train T, and also travels at a constant speed of y mph. Will they meet closer to A or to B?
1) y>x
2) They finished their trips at the same time
ONE
INSUFF ...WE NEED TO KNOW THE TIME LAPSED BETWEEN BOTH TRAINS LEAVING THE STATIONS
2) IF THEY REACHED THE SAME DITINATION AT THE SAME TIME
THEN
THEY MET CLOSER TO A
MY ANSWER IS B



Senior Manager
Joined: 05 Oct 2006
Posts: 266

Re: DS: Train [#permalink]
Show Tags
15 Oct 2006, 23:17
u have to know how much time later train s started in order to know where they meet...
choice 1...insufficient.
choice 2... if they finished at the same time ..means y>x...nothing can be said when they met..???..insufficient..
choice E as per me..
what's the OA???



Manager
Joined: 03 Jul 2005
Posts: 192
Location: City

Train T leaves from town A for town B and travels at a constant speed of x mph. Train S leaves town B for town A, later than the train T, and also travels at a constant speed of y mph. Will they meet closer to A or to B?
1) y>x
2) They finished their trips at the same time
I would say E as well
Since we don't know how much later train S leaves than train T.
What is the OA?



Senior Manager
Joined: 22 Sep 2005
Posts: 276

I haven't got OA, but in my opinion is E too.
1) NS, because although y>x, and train S leaves after train T, we can't know where they are going to meet.
2) NS. If they finished their trips at the same time, we deduce that y>x, and we knew that is NS.
1) and 2) are NS, because both give the same information.
So in my opinion the answer is E.



Manager
Joined: 12 Sep 2006
Posts: 91

answer must be B
(1) is insufficient for obvious reasons
(2) is sufficient, best way to see it is by drawing it on paper. We know that both trains finish their trips at the same time, so we know y>x
If we cut the distance in half, train S will be in the middle and, regardless of how much slower train T is, it will always be a little bit closer to B, therefore they meet closer to town B



Intern
Joined: 28 Jun 2006
Posts: 9

I agree with E.
By using both statements, I can think of situations which produce both answers.
Since we don't know how long train S waits to leave or how fast either of them go, train S could leave either before S gets to the halfway point, or after train S gets to the halfway point.
If train S waits to leave until train T has reached the halfway point, then they meet closer to B. If train S leaves only shortly after train T and travels much faster, then train S could pass the midway point of the track before train T does.
Sorry if the post is a little convoluted.



Director
Joined: 23 Jun 2005
Posts: 841

B
If train S leaves later than T, but finishes at the same time, then T is traveling faster than S.
So, when they meet, the distance between the meeting point and B should be smaller than the distance between the meeting point and A. So, statement 2 is SUFF



Manager
Joined: 31 Aug 2006
Posts: 210

anandsebastin wrote: B
If train S leaves later than T, but finishes at the same time, then T is traveling faster than S. So, when they meet, the distance between the meeting point and B should be smaller than the distance between the meeting point and A. So, statement 2 is SUFF
IF If train S leaves later than T, but finishes at the same time, then S is traveling faster than T and not vice versa..Can you pls. explain in little detail that how is it (B) ..and what is the OA ?



Manager
Joined: 07 Jun 2006
Posts: 109

Code: If train S leaves later than T, but finishes at the same time, then T is traveling faster than S. So, when they meet, the distance between the meeting point and B should be smaller than the distance between the meeting point and A. So, statement 2 is SUFF
Anand, What if the difference in rates is negligible and the difference in time is huge???
Without actual numbers, its hard to decide on the meeting point. It can fall in either of the halves, depending on the difference in rates and difference in time.
Correct me if this line of thinking is wrong.



Senior Manager
Joined: 01 Oct 2006
Posts: 495

I guess B2 for the same reason as Anand



Manager
Joined: 04 May 2006
Posts: 172
Location: paris

two extreme examples
d=100
trains S =10, then T=10h
Train T :y=100 then T=1h
they meet closer to B
or
d=120
x=10, then T=12h
y=10,1 then T=11,88h
they meet closer to B
since right after T=6h
S is closer to B
and
T has not crossed the mid distance yet since it left 0,12h late... and it will cross the mid point at 0.12h+ 11,88/2=5,94+,12=6,16h
hope it helps
_________________
time is not on my side










