Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
Train A leaves New York for Boston at 3 PM and travels at [#permalink]
15 Sep 2006, 13:51
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 re-post it in the respective forum.
Train A leaves New York for Boston at 3 PM and travels at the constant speed of 100 mph. An hour later, it passes Train B, which is making the trip from Boston to New York at a constant speed. If Train B left Boston at 3:50 PM and if the combined travel time of the two trains is 2 hours, what time did Train B arrive in New York?
(1) Train B arrived in New York before Train A arrived in Boston.
(2) The distance between New York and Boston is greater than 140 miles.
I think D is the answer.
This is the way I went about it and I am not sure if I am right (I am an absolute novice here and this is my first post ever!)
Let the distance between NY and Boston be y miles
Let the speed of train B be x miles/hr.
We know speed of A is 100 miles/hr.
Since combined travel time of both trains to travel to their destination is 2 hours,
y/x + y/100 =2
1 hour after A has left NY(i.e 4 pm), both the trains meet each other.
In 1 hour, distance covered by A is 100 miles.
At 4pm, Train B has travelled 10 minutes only(since it starts from Boston at 3.50 pm), so distance covered by B is x/6 miles.
When both the trains meet, together they have covered the distance between NY and Boston.
Hence, 100+ x/6 = y
Substituting Y in the prev equation,
x=300 for which y=150
x=200 for which y=133.33
But since Statement 2 says distance y should be greater than 140 miles, statement 2 alone answers this query at this stage.
If we calculate further,
If y=150 miles, then train B will take 30 mins to reach NY which calculates to 4.20 pm and A will take 1.5 hours which calculates to 4.30 pm.
If y=133.33 miles, then train B will take apprx 40 mins to reach NY which calculates to 4.30 pm and A will take approx 1 hour 20 mins, which makes it 4.20 pm.
Statement 1 says train B arrived in NY before train A arrived in Boston and this is true for y=150 miles.
Thus each statement alone is sufficient to answer this query.