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

It is currently 24 May 2019, 08:11

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

Train A leaves New York at 9am Eastern Time on Monday

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

Hide Tags

 
Intern
Intern
avatar
Joined: 26 Aug 2013
Posts: 2
Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 10 Sep 2013, 05:39
3
14
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

56% (03:02) correct 44% (03:31) wrong based on 175 sessions

HideShow timer Statistics

Train A leaves New York at 9am Eastern Time on Monday, headed for Los Angeles at a constant rate of 40 miles per hour. On the same 3,000-mile stretch of track, Train B leaves Los Angeles at noon Eastern Time on Monday, traveling to New York at its constant rate of 60 miles per hour, with one exception: Train B is delayed for exactly 2 hours in Las Vegas (approximately 200 miles from Los Angeles) due to track maintenance. Assuming the time it takes for Train B to decelerate and re-accelerate when stopping and resuming in Las Vegas is negligible, at what time (Eastern Time) will the two trains meet?

A) 3:00pm on Tuesday
B) 4:30pm on Tuesday
C) 5:00pm on Tuesday
D) 6:00pm on Tuesday
E) 7:30pm on Tuesday
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55271
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 10 Sep 2013, 05:47
8
7
Manaswita wrote:
Train A leaves New York at 9am Eastern Time on Monday, headed for Los Angeles at a constant rate of 40 miles per hour. On the same 3,000-mile stretch of track, Train B leaves Los Angeles at noon Eastern Time on Monday, traveling to New York at its constant rate of 60 miles per hour, with one exception: Train B is delayed for exactly 2 hours in Las Vegas (approximately 200 miles from Los Angeles) due to track maintenance. Assuming the time it takes for Train B to decelerate and re-accelerate when stopping and resuming in Las Vegas is negligible, at what time (Eastern Time) will the two trains meet?

A) 3:00pm on Tuesday
B) 4:30pm on Tuesday
C) 5:00pm on Tuesday
D) 6:00pm on Tuesday
E) 7:30pm on Tuesday


We can assume that B leaves Los Angeles not at noon but at 2pm Eastern Time, so 5 hours later than A leaves New York.

In 5 hours A covers 5*40=200 miles. So, A and B together should cover 3,000-200=2,800 miles.

Combined rate = 40 + 60 = 100 miles per hour.

To cover 2,800 miles they'll need 2,800/100=28 hours.

2pm Eastern Time on Monday + 28 hours = 6pm Eastern Time on Tuesday.

Answer: D.
_________________
General Discussion
Senior Manager
Senior Manager
User avatar
Joined: 13 May 2013
Posts: 420
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 10 Sep 2013, 11:29
Train A leaves New York at 9am Eastern Time on Monday, headed for Los Angeles at a constant rate of 40 miles per hour. On the same 3,000-mile stretch of track, Train B leaves Los Angeles at noon Eastern Time on Monday, traveling to New York at its constant rate of 60 miles per hour, with one exception: Train B is delayed for exactly 2 hours in Las Vegas (approximately 200 miles from Los Angeles) due to track maintenance. Assuming the time it takes for Train B to decelerate and re-accelerate when stopping and resuming in Las Vegas is negligible, at what time (Eastern Time) will the two trains meet?

I think I am being thrown off by Train A starting before train B. How do I figure out how long it takes for them to meet one another if one train starts off before the other?
Director
Director
User avatar
S
Joined: 17 Dec 2012
Posts: 630
Location: India
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 10 Sep 2013, 16:58
2
WholeLottaLove wrote:
Train A leaves New York at 9am Eastern Time on Monday, headed for Los Angeles at a constant rate of 40 miles per hour. On the same 3,000-mile stretch of track, Train B leaves Los Angeles at noon Eastern Time on Monday, traveling to New York at its constant rate of 60 miles per hour, with one exception: Train B is delayed for exactly 2 hours in Las Vegas (approximately 200 miles from Los Angeles) due to track maintenance. Assuming the time it takes for Train B to decelerate and re-accelerate when stopping and resuming in Las Vegas is negligible, at what time (Eastern Time) will the two trains meet?

I think I am being thrown off by Train A starting before train B. How do I figure out how long it takes for them to meet one another if one train starts off before the other?


When the trains travel towards each other, we have to consider the combined speed but only when one of them travel we have to consider only that train's speed.

1. Here, for the first 3 hours i.e., between 9 am and 12 noon only train A travels. The distance covered by it is 3*40 = 120 miles. The remaining distance is 3000-120=2880 miles

2. Also after that for exactly 2 hours train A only travels because train B stops at Las Vegas for 2 hours. The distance covered by train A during this period is 2*40=80 miles. Remaining distance is 2880-80=2800 miles

3. The distance of 2800 miles is covered with both trains moving towards each other. Therefore for this distance combined speed is to be taken. Time taken to cover 2800 miles = 2800/(60+40) = 28 hours.

4. Train A traveled for 5 hours alone and for 28 hours together with train B. The total hours traveled by A is 33 hours. Since it started at 9 am on Monday the two trains will meet 33 hours later i.e., 6 pm on Tuesday.
_________________
Srinivasan Vaidyaraman
Sravna Test Prep
http://www.sravnatestprep.com

Holistic and Systematic Approach
LBS Thread Master
avatar
B
Joined: 13 Jan 2015
Posts: 97
Location: United Kingdom
Concentration: Other, General Management
Schools: LBS '19 (WL)
GMAT 1: 690 Q48 V36
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 08 Feb 2016, 16:44
1
my issue with this question is that, are we not to take into consideration the distance travelled by Train B from Los Angeles to Las Vegas (approx 200 miles). Does that not factor into the overall distance travelled??

Would love to hear some analysis..
Intern
Intern
avatar
B
Joined: 01 Feb 2019
Posts: 15
GMAT ToolKit User
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 22 Mar 2019, 20:56
To benefit the GMATClub community, please avoid the same mistake that I did. Took way too long to graph the journey, got thrown off scent by the whole Train B delayed in Vegas thing.

Action item: I think Bunuel's solution is the most actionable for me given exam situation.

I need to retrain my brain to stop relying so much on graphing the questions because it is hurting my GMAT score and not helping at all. This has happened several times, so I suspect I just need to train my brain to framework this type of Problem to Bunuel's template and just get on with the math. Next step is for me to try, embed this to muscle memory, see if there is any improvement in timing & accuracy.
Manager
Manager
avatar
B
Joined: 09 Nov 2015
Posts: 70
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 04 Apr 2019, 01:53
Just to be clear, I am basing my calculations on the assumption that all times (both for Train A and B) are Eastern Time since the question clearly states so.

Train B starts from LA at 12 noon, reaches Vegas at 3:20 pm (3 hrs 20 mins to cover 200 miles at 60 mph) and leaves Vegas at 5:20 pm (2 hrs delay).
By this time, Train A, which had left NY at 9:00 am, had already been travelling been travelling for 8 hrs 20 mins (25/3 hrs) in which time it had covered approximately 333 miles (25/3*40).
So at 5:20 pm, Trains A and B had together covered (333+200)= 533 miles of the 3000 miles and only 2457 miles separated them.
Let assume the two trains meet after 't' hrs from this point. So, in 't' hrs Trains A and B will cover 40*t and 60*t miles respectively.
Thus, 60t+40t=2457---> t=24.67 hrs=24 hrs 40 mins. So, the two trains will meet at 6:00 pm on Tuesday. Ans: D
Manager
Manager
avatar
B
Joined: 09 Nov 2015
Posts: 70
Re: Train A leaves New York at 9am Eastern Time on Monday  [#permalink]

Show Tags

New post 04 Apr 2019, 23:03
Took another look at the problem and found a simpler and faster solution:
Let's say Train A (TA) travels for 't' hrs after its departure from NY up to the point it meets Train B (TB). Thus, TB travels for (t -5)hrs since it started 3 hrs after TA and lost an additional 2 hrs at Vegas. So TA and TB travel t*40 miles and (t-5)*60 miles respectively to cover the 3000 miles between NY and LA.
So, 40*t +60*(t-5) = 3000 ----> t = 33 hrs. Since TA started at 9:00 am Monday, the two trains will meet at 6:00 pm Tuesday.
GMAT Club Bot
Re: Train A leaves New York at 9am Eastern Time on Monday   [#permalink] 04 Apr 2019, 23:03
Display posts from previous: Sort by

Train A leaves New York at 9am Eastern Time on Monday

  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®.