It is currently 20 Mar 2018, 16:31

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If two trains ,travelling at a speed of 72mph and 48 mph respectively,

Author Message
TAGS:

### Hide Tags

Senior SC Moderator
Joined: 14 Nov 2016
Posts: 1284
Location: Malaysia
If two trains ,travelling at a speed of 72mph and 48 mph respectively, [#permalink]

### Show Tags

11 Mar 2017, 19:02
4
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

71% (00:54) correct 29% (01:38) wrong based on 136 sessions

### HideShow timer Statistics

If two trains ,travelling at a speed of 72mph and 48 mph respectively, are approaching each other from opposite direction; what is the distance between them 1 minute before the collision ?

A)2 miles
B)3 miles
C)4 miles
D)5 miles
E)none of the above.
[Reveal] Spoiler: OA

_________________

"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."

Manager
Joined: 27 Aug 2014
Posts: 55
Concentration: Strategy, Technology
GMAT 1: 660 Q45 V35
GPA: 3.66
WE: Consulting (Consulting)
Re: If two trains ,travelling at a speed of 72mph and 48 mph respectively, [#permalink]

### Show Tags

11 Mar 2017, 19:08
Relative speed between them = 48+72 MPH.

The distance they both will cover in a minute = (48+72)/60 = 2.

Hence A.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 11292
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Re: If two trains ,travelling at a speed of 72mph and 48 mph respectively, [#permalink]

### Show Tags

13 Mar 2017, 11:21
Expert's post
1
This post was
BOOKMARKED
Hi ziyuen,

When two entities (people, trains, etc.) are approaching one another, you have to consider the COMBINED speed that they're traveling - and the TOTAL DISTANCE that they're covering together. Here, we have two trains - traveling 72 mph and 48 mph - so combined, they travel 120 miles per hour. That means they travel a total of 120/60 = 2 miles per minute. Thus, when they're 1 minute from 'meeting', the distance between them is 2 miles.

[Reveal] Spoiler:
A

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save \$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

SVP
Joined: 12 Sep 2015
Posts: 2153
Re: If two trains ,travelling at a speed of 72mph and 48 mph respectively, [#permalink]

### Show Tags

14 Nov 2017, 08:43
2
KUDOS
Expert's post
Top Contributor
hazelnut wrote:
If two trains ,travelling at a speed of 72mph and 48 mph respectively, are approaching each other from opposite direction; what is the distance between them 1 minute before the collision ?

A)2 miles
B)3 miles
C)4 miles
D)5 miles
E)none of the above.

I call this a shrinking gap question.

When we ADD the speeds of the trains, we get 72 mph + 48 mph = 120 mph
This means, the gap SHRINKS at a rate of 120 miles per HOUR
We can also say that the gap SHRINKS at a rate of 2 miles per MINUTE

What is the distance between them 1 minute before the collision ?
Since the gap SHRINKS at a rate of 2 miles per MINUTE, we can conclude that, 1 minute before the collision, the trains will be 2 miles apart.

RELATED VIDEO FROM OUR COURSE

_________________

Brent Hanneson – Founder of gmatprepnow.com

Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3367
Location: India
GPA: 3.5
Re: If two trains ,travelling at a speed of 72mph and 48 mph respectively, [#permalink]

### Show Tags

14 Nov 2017, 11:12
hazelnut wrote:
If two trains ,travelling at a speed of 72mph and 48 mph respectively, are approaching each other from opposite direction; what is the distance between them 1 minute before the collision ?

A)2 miles
B)3 miles
C)4 miles
D)5 miles
E)none of the above.

Distance is $$\frac{72+48}{60}$$ Miles/min = 2 Miles/Min

So, The distance between them 1 minute before the collision is 2 Miles, answer will be (A)
_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Re: If two trains ,travelling at a speed of 72mph and 48 mph respectively,   [#permalink] 14 Nov 2017, 11:12
Display posts from previous: Sort by