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

It is currently 19 Aug 2018, 18:40

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

Andrew and Stephen drive on the highway in the same direction at respe

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

Hide Tags

Retired Moderator
User avatar
Joined: 18 Jul 2008
Posts: 893
Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 22 Apr 2009, 17:49
6
27
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

78% (01:35) correct 22% (01:52) wrong based on 534 sessions

HideShow timer Statistics

Andrew and Stephen drive on the highway in the same direction at respective rates of 72 and 80 kmh. If Stephen is 4 km behind Andrew, by how much does he have to increase his speed to catch up with Andrew in 20 minutes?

A. 1 kmh
B. 2 kmh
C. 3 kmh
D. 4 kmh
E. 5 kmh

M17-37
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 48037
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 19 Oct 2014, 02:58
2
7
bigfernhead wrote:
Andrew and Stephen drive on the highway in the same direction at respective rates of 72 and 80 kmh. If Stephen is 4 km behind Andrew, by how much does he have to increase his speed to catch up with Andrew in 20 minutes?

A. 1 kmh
B. 2 kmh
C. 3 kmh
D. 4 kmh
E. 5 kmh

M17-37


Denote the required acceleration as \(x\). The distance between Andrew and Stephen will be decreasing at \((80 + x - 72)\) kmh. We can compose the equation \(\frac{4}{80 + x - 72} = \frac{20}{60}\) from which \(x = 4\).

Answer: D
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Most Helpful Community Reply
Manager
Manager
avatar
Joined: 30 Nov 2008
Posts: 91
GMAT ToolKit User
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 25 Jul 2009, 13:42
11
7
I think its much easier to first assume that they are going the same speed. So he has to catch up 4 meters in 1/3 hour. r= d/t = 4/(1/3) = 12 km/hr faster he has to go. He is already going 8km/h faster, so 12 - 8 = 4 km/hr
General Discussion
Senior Manager
Senior Manager
avatar
Joined: 08 Jan 2009
Posts: 310
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 22 Apr 2009, 18:44
2
4
A -- 72 Kmh
B -- 80 Kmh

Relative speed = 8 kmh

distance b/w them = 4 Km

4 /( 80 +x - 72) = 20/60

solve for x = 4 .....

Ans . D
Intern
Intern
avatar
Joined: 02 May 2009
Posts: 1
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 02 May 2009, 07:36
4
If x is the distance travelled by Andrew in 20 minutes = 72*20/60 = 24km

Stephen's speed would to travel (24+4)km = 28*60/20 = 84 km/h

So, answer is D - 4km/h
_________________

Goal is 700+

B The Best U

Manager
Manager
User avatar
Joined: 19 Aug 2006
Posts: 225
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 02 May 2009, 15:25
2
2
relative speed=80-72=8
need to catch up 4km

currently Stephen is catching up at a speed of 4km/30mins, or 2km/15mins
he needs to increase the speed, so that he can make 4km in 20 mins instead, or 1km/5mins

x - the relative speed increase we seek
2/15+x=1/5
x=1/15

So, he needs to increase relative speed by 1km per 15mins, or 4km/h
Therefore, the answer is D.
VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1069
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 12 Nov 2015, 20:04
4k/8kph=1/2h
4k/(8+x)kph=1/3h
x=4kph faster
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3182
Location: United States (CA)
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 03 Feb 2017, 12:47
1
1
bigfernhead wrote:
Andrew and Stephen drive on the highway in the same direction at respective rates of 72 and 80 kmh. If Stephen is 4 km behind Andrew, by how much does he have to increase his speed to catch up with Andrew in 20 minutes?

A. 1 kmh
B. 2 kmh
C. 3 kmh
D. 4 kmh
E. 5 kmh



We can classify this problem as a “catch-up” rate problem, for which we use the formula:

distance of Andrew + 4 = distance of Stephen

We are given that Andrew is driving at a rate of 72 kmh and that Stephen is driving at a rate of 80 kmh. We need to determine how much faster Stephen needs to drive to catch up to Andrew in 20 minutes or 20/60 = 1/3 hour.

If we let r = Stephen’s speed increase, we can say the following:

distance of Stephen = (r + 80)(1/3) = (r + 80)/3

distance of Andrew + 4 = 72 x 1/3 + 4 = 28

We can equate the two distances and determine r.

(r + 80)/3 = 28

r + 80 = 84

r = 4

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Senior Manager
Senior Manager
User avatar
S
Status: love the club...
Joined: 24 Mar 2015
Posts: 278
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 03 Nov 2017, 11:17
bigfernhead wrote:
Andrew and Stephen drive on the highway in the same direction at respective rates of 72 and 80 kmh. If Stephen is 4 km behind Andrew, by how much does he have to increase his speed to catch up with Andrew in 20 minutes?

A. 1 kmh
B. 2 kmh
C. 3 kmh
D. 4 kmh
E. 5 kmh

M17-37


given
4/8 = 1/2

to make it 1/3, we need to change 8 to 12
so the difference is 4

thanks
Manager
Manager
User avatar
G
Joined: 07 Jun 2017
Posts: 175
Location: India
Concentration: Technology, General Management
GMAT 1: 660 Q46 V38
GPA: 3.6
WE: Information Technology (Computer Software)
GMAT ToolKit User Reviews Badge
Re: Andrew and Stephen drive on the highway in the same direction at respe  [#permalink]

Show Tags

New post 04 Nov 2017, 21:35
Relative speed = 8 kmh

distance b/w them = 4 Km

4 /( 80 +x - 72) = 20/60

Answer D
_________________

Regards,
Naveen
email: nkmungila@gmail.com
Please press kudos if you like this post

Re: Andrew and Stephen drive on the highway in the same direction at respe &nbs [#permalink] 04 Nov 2017, 21:35
Display posts from previous: Sort by

Andrew and Stephen drive on the highway in the same direction at respe

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


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®.