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

 It is currently 26 Apr 2019, 08:56

### 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

# Identical trains A and B are traveling non-stop on parallel tracks fro

Author Message
TAGS:

### Hide Tags

Senior SC Moderator
Joined: 14 Nov 2016
Posts: 1330
Location: Malaysia
Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

16 Feb 2017, 20:33
7
00:00

Difficulty:

35% (medium)

Question Stats:

72% (02:14) correct 28% (02:19) wrong based on 173 sessions

### HideShow timer Statistics

Identical trains A and B are traveling non-stop on parallel tracks from New York to Chicago. Train A leaves New York at 5PM and travels at a constant speed of 55mph (assume constant speed from start of trip). Train B leaves New York at 6:12PM and travels at a constant speed of 66mph (assume constant speed from start of trip). At what time will the two trains be exactly beside each other?

(A) 6:00PM
(B) 7:12PM
(C) 12:00AM
(D) 12:12AM
(E) 1:12AM

_________________
"Be challenged at EVERY MOMENT."

“Strength doesn’t come from what you can do. It comes from overcoming the things you once thought you couldn’t.”

"Each stage of the journey is crucial to attaining new heights of knowledge."

Intern
Joined: 03 Jan 2017
Posts: 30
Re: Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

16 Feb 2017, 21:06
Speed of trains
A: 55 mph
B: 66 mph
Rate at which B is reaching towards A= B-A = 11mph

Distance between A and B = 72 mins*55 miles/60 mins

Time taken by B to reach A= 72*55/60/11
=72*55/60*11
= 6 hrs.
So 6.12pm + 6 hrs= 12.12 am.
Option D is the right answer

Sent from my MotoG3 using GMAT Club Forum mobile app
Manager
Joined: 19 Jul 2017
Posts: 85
Location: India
Concentration: General Management, Strategy
GPA: 3.5
Re: Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

06 Sep 2017, 05:10
1
hazelnut wrote:
Identical trains A and B are traveling non-stop on parallel tracks from New York to Chicago. Train A leaves New York at 5PM and travels at a constant speed of 55mph (assume constant speed from start of trip). Train B leaves New York at 6:12PM and travels at a constant speed of 66mph (assume constant speed from start of trip). At what time will the two trains be exactly beside each other?

(A) 6:00PM
(B) 7:12PM
(C) 12:00AM
(D) 12:12AM
(E) 1:12AM

By 6:12 Train A would have travelled 66 miles(55 miles in an hr and 11 miles in 12 mins) ahead.

When they meet x*66 = x*55+66;
11x= 66.

Therefore x=6.
so Time would be 6:12+6.
Hence 12:12. Ans:D
Senior SC Moderator
Joined: 22 May 2016
Posts: 2654
Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

06 Sep 2017, 09:41
hazelnut wrote:
Identical trains A and B are traveling non-stop on parallel tracks from New York to Chicago. Train A leaves New York at 5PM and travels at a constant speed of 55mph (assume constant speed from start of trip). Train B leaves New York at 6:12PM and travels at a constant speed of 66mph (assume constant speed from start of trip). At what time will the two trains be exactly beside each other?

(A) 6:00PM
(B) 7:12PM
(C) 12:00AM
(D) 12:12AM
(E) 1:12AM

Using the gap method in a "chase" scenario.

Train A, while traveling alone, creates the distance (gap) between the trains.

Train A travels alone for $$\frac{6}{5}$$ hours * 55 miles/hour = 66 miles

At 6:12 p.m., both trains are moving. But Train B travels faster than train A and will overtake A.

When travelers move in the same direction, subtract slower rate from faster rate to get the rate at which the gap shrinks (relative speed). 66 - 55 = 11 mph

How long will it take for B to catch A? D/r = t. D is 66. r is 11. 66/11 = 6 hours

The clock time at which they are "exactly beside one another" is calculated from the time B leaves, which is when both trains are traveling and the gap begins to shrink.

Add 6 hours to 6:12 p.m. Train B catches Train A at 12:12 a.m.

_________________
Listen, are you breathing just a little, and calling it a life?
-- Mary Oliver

For practice SC questions with official explanations that were posted and moderated by the SC Team,
go to SC Butler here: https://gmatclub.com/forum/project-sc-butler-get-2-sc-questions-everyday-281043.html
Intern
Joined: 03 Dec 2015
Posts: 7
Location: United States (TX)
Concentration: Strategy, General Management
GPA: 3.64
Re: Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

06 Sep 2017, 11:03

If you wanted to work the problem, it is very easy to remove choices a and b before doing any calculations:

A: 6:00 pm (Train A would have moved for 1.2 hrs at 55 mph while Train B would have made no distance at all)
B: 7:12 pm (Train B would have moved just 1 hr at 66 mph while Train A would have been moving for 2.2 hrs at 55 mph)
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 5872
Location: United States (CA)
Re: Identical trains A and B are traveling non-stop on parallel tracks fro  [#permalink]

### Show Tags

11 Sep 2017, 10:56
hazelnut wrote:
Identical trains A and B are traveling non-stop on parallel tracks from New York to Chicago. Train A leaves New York at 5PM and travels at a constant speed of 55mph (assume constant speed from start of trip). Train B leaves New York at 6:12PM and travels at a constant speed of 66mph (assume constant speed from start of trip). At what time will the two trains be exactly beside each other?

(A) 6:00PM
(B) 7:12PM
(C) 12:00AM
(D) 12:12AM
(E) 1:12AM

We can let the time of train B = t. Train A left 72 minutes earlier than train B, which is 72/60 hours, and thus the time of train A = t + 72/60 = t + 6/5.

Using the formula distance = rate x time, the distance of train A is 55(t + 6/5) = 55t + 66 and distance train B is 66t.

Thus:

distance train A = distance train B

55t + 66 = 66t

66 = 11t

6 = t

So, the trains are besides each other at 6:12 p.m. + 6 hours = 12:12 a.m.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

Re: Identical trains A and B are traveling non-stop on parallel tracks fro   [#permalink] 11 Sep 2017, 10:56
Display posts from previous: Sort by