Train A started from Station X toward Station Y traveling at

Question

Train A started from Station X toward Station Y traveling at a constant speed, and on the same day, on a parallel track, Train B started from Station Y toward Station X at a constant speed. At what time did Train A reach Station Y?

(1) The two trains met at 3:00 p.m. The distance traveled by Train A was twice the distance traveled by Train B by the time they met.

(2) The ratio between the speeds of Trains A and B is 3:5. Train B started from Station Y at 6:00 a.m.

PReciSioN · Accepted Answer

When both statements are taken together, it implies that train A started the previous day which contradicts the stimulus.

MartyMurray · Answer

Train A started from Station X toward Station Y traveling at a constant speed, and on the same day, on a parallel track, Train B started from Station Y toward Station X at a constant speed. At what time did Train A reach Station Y?

To determine the time at which Train A reached Station Y, we need some information about the time of day at which the trains were traveling and, unless that information is the time of day at which Train A reached Station Y, we'll also need some information indicating Train A's speed.

(1) The two trains met at 3:00 p.m. The distance traveled by Train A was twice the distance traveled by Train B by the time they met.

This choice does mention a time of day, 3:00 pm.

However, since the trains could have traveled for any amount of time before and after they met, this information is not sufficient for determining when Train A reached Station Y.

Insufficient.

(2) The ratio between the speeds of Trains A and B is 3:5. Train B started from Station Y at 6:00 a.m.

This choice does mention a time of day, 6:00 am.

However, since it doesn't provide reference points or other information, such as distance, the exact speed of either train, when Train A departed, or when either train arrived at its destination, that we can use to determine when either train arrived at its destination, this choice is not sufficient for answering the question.

Insufficient.

(1) and (2) combined

Combined, the two statements provide reference points and other information sufficient for determining when Train A reached Station Y. Here's how.

From statement (1):  The two trains met at 3:00 p.m. The distance traveled by Train A was twice the distance traveled by Train B by the time they met.

So, A was 2/3 of the way from Station X to Station Y when they met at 3:00 pm, and Train B had traveled 1/3 of the distance between the stations.

From statement (2):  Train B started from Station Y at 6:00 a.m.

So, it took Train B from 6:00 am to 3:00 pm, or 9 hours, to travel 1/3 of the way. Thus, we now know Train B's rate in terms of the route: the entire route will take Train B 27 hours.

From statement (2):  The ratio between the speeds of Trains A and B is 3:5.

Since we can calculate Train B's rate from the previous information, we can use that rate along with this information from statement (2) to calculate Train A's rate, which is 3/5 of Train B's rate.

We also know from the previous information that Train A has 1/3 of the route left to travel at 3:00 pm.

We don't need to calculate the actual time of arrival of Train A. All we have to do is see that, knowing Train A's rate and how much of the route Train A had left to travel at 3:00 pm, we could calculate when Train A arrived at Station Y.

Sufficient.

Correct answer:  C

sayan640 · Answer

The first statement is NOT sufficient because we dont know at what time the trains started.

The second statement is NOT statement beacuse we dont know at what time the train A started.\

Together ,

A's speed = 3x
B's speed = 5x
B travelled = 5x * 9 = 45x  meter
After meeting A need to travel 45x meters at the speed of 3x.

A will take = 45x / 3x = 15 hours.

So they will meet at 3 pm + 15 hours = 6 am morning

C is the answer.  
Kindly check   chetan2u   GMATinsight   KarishmaB

KarishmaB · Answer

I am not sure what to make of the question. If it is an official question and correct, then perhaps I am missing something, but I cannot say what.

Using both statements we can see  that ratio of speeds is 3:5, train B started at 6:00 AM (say on 3rd July) and they met at 3:00 PM (assuming on 3rd July) so train B had travelled for 9 hrs in this time. 
Ratio of distance covered by the two trains = 2:1

\frac{SpeedA * TimeA }{ SpeedB * TimeB}  = \frac{2}{1}

\frac{3s * TimeA }{ 5s * 9}  = \frac{2}{1}

TimeA = 30 hrs

This means that train A started 30 hrs prior to 3:00 PM which means 9:00 AM of previous day (of 2nd July). But in the question, we are given that 
"Train A started from Station X toward Station Y traveling at a constant speed, and  on the same day , on a parallel track, Train B started from Station Y toward Station X at a constant speed"
and I see inconsistency in the data here.

Of course, we can just go on and ignore the highlighted to get the answer as "train A took 30 hrs to cover 2/3rd of distance and hence will take another 15 hrs to cover the remaining 1/3rd and hence we can get the time at which it will reach Y. So both statements together would be sufficient.

guddo · Answer

This from new OG: https://gmatclub.com/forum/download/file.php?id=82405 https://gmatclub.com/forum/download/file.php?id=82406 https://gmatclub.com/forum/download/file.php?id=82407 GMAT-Club-Forum-vd7op10p.png GMAT-Club-Forum-aj0b8tng.png GMAT-Club-Forum-p8ydywyp.png

Gemmie · Answer

Statement 1:

A  ==>                      <==B
(X) ----------------- --------(Y)

MP: meeting point

And we know that 2 trains meet at 18:00

==> Insufficient

Statement 2:

a: Train A's speed
b: Train B's speed

\frac{a}{b} = \frac{3}{5}

And we know train B starts from 6:00

==> Insufficient

Combined:

\frac{a}{b} = \frac{3}{5} 
=> a = 3k; b = 5k

Time train A travels from meeting point till destination Y:  \frac{x}{3k}

Time train B has traveled until meeting point:  \frac{x}{5k} = 18 - 6 = 12

=> We can find  \frac{x}{k}

=> We can find  \frac{x}{3k}

=> Sufficient

=> BOTH statements TOGETHER are sufficient

Emily1122 · Answer

bb  could you please help? Is there a typo in the question? The question says they start on the same day. How is it on the same day?

Train A and Train B start from opposite stations on the same day, traveling toward each other on parallel tracks at constant speeds.

Statement (1): They met at 3:00 p.m., and by then Train A had traveled twice the distance of Train B.

Statement (2): The speed ratio of Train A to Train B is 3:5, and Train B started from its station at 6:00 a.m.

So with statement 2, Train B travels for 9 hours before they meet (from 6:00 a.m. to 3:00 p.m.), covering 45 miles at 5 mph.

Train A, having gone twice the distance (90 miles) at 3 mph, would have needed 30 hours to reach the meeting point.

But if they met at 3:00 p.m., this means Train A must have started at 9:00 a.m. the day before, which contradicts the condition that both trains started on the same day.

Can you confirm whether the question has an error or if there’s something I’m missing?

PocusFocus · Answer

If the ratio of the speed between A and B is 3 to 5, how the distance Traveled by Train A was twice the distance by the Train B in the moment the met?
For this reason C cannot be an answer, right?
What am I missing?

architectodicta · Answer

Hi,

I believe they started in different times.

We know that at a 5x rate, train B traveled 1/3d in 9 hours because it started at 6:00 am.

However, we don't know when train A started.

But we can solve D in terms of X with this info because:

5X . 9 = 45x

and 45x = 1/3d travelled by train B

So train A will travel 45x . 3 = total distance with 3x.

Train A started from Station X toward Station Y traveling at

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