Find all School-related info fast with the new School-Specific MBA Forum

It is currently 01 Feb 2015, 11:42

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A car travels from Town A to Town B at an average speed

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Manager
Manager
User avatar
Joined: 28 May 2009
Posts: 155
Followers: 4

Kudos [?]: 110 [1] , given: 89

GMAT ToolKit User
A car travels from Town A to Town B at an average speed [#permalink] New post 05 Jan 2013, 17:08
1
This post received
KUDOS
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

77% (02:19) correct 23% (00:40) wrong based on 132 sessions
A car travels from Town A to Town B at an average speed of 40 miles per hour, and returns immediately along the same route at an average speed of 50 miles per hour. What is the average speed in miles per hour for the round-trip?

(A) 45\frac{4}{9} mph

(B) 44 mph

(C) 45 mph

(D) 44\frac{4}{9} mph

(E) 44\frac{1}{9} mph
[Reveal] Spoiler: OA

_________________

New to GMAT Club? Start here

Kindle Flashcards - Quant (Official Gmat Club, miguemick's Quant topics), and Verbal (Official Gmat Club) - in Kindle (azw3) format

2 KUDOS received
Current Student
User avatar
Joined: 27 Jun 2012
Posts: 418
Concentration: Strategy, Finance
Followers: 54

Kudos [?]: 411 [2] , given: 182

Re: A car travels from Town A to Town B at an average speed [#permalink] New post 05 Jan 2013, 17:47
2
This post received
KUDOS
Using "Pick numbers" strategy, assume total distance as 200 miles. (LCM of 40 & 50)

Time taken to travel from A to B = 200/40 = 5 hours
Time taken to travel from B to A = 200/50 = 4 hours

Average(speed) = \frac{{Total (Distance) }}{{ Total (Time) }}= \frac{(200+200)}{(5+4)} = \frac{400}{9} = 44 \frac{4}{9}

Hence Choice(D).
_________________

Thanks,
PraPon

Tough 700+ Level RCs: Passage1 | Passage2 | Passage3 | Passage4 | Passage5 | Passage6 | Passage7
Reading Comprehension notes: Click here
VOTE: vote-best-gmat-practice-tests-excluding-gmatprep-144859.html
PowerScore CR Bible - Official Guide 13 Questions Set Mapped: Click here

Expert Post
1 KUDOS received
e-GMAT Representative
User avatar
Joined: 02 Nov 2011
Posts: 1818
Followers: 1374

Kudos [?]: 4044 [1] , given: 203

Re: A car travels from Town A to Town B at an average speed [#permalink] New post 08 Jan 2013, 01:07
1
This post received
KUDOS
Expert's post
megafan wrote:
A car travels from Town A to Town B at an average speed of 40 miles per hour, and returns immediately along the same route at an average speed of 50 miles per hour. What is the average speed in miles per hour for the round-trip?

(A) 45\frac{4}{9} mph

(B) 44 mph

(C) 45 mph

(D) 44\frac{4}{9} mph

(E) 44\frac{1}{9} mph


Hi,

This is a classic question on Speed, time, & distance.

1. When time traveled in each segment is constant, then average speed is simple mean of speeds.

2. When distance traveled in each segment is constant, then average speed is reciprocal of simple mean of reciprocal of speeds. It is basically called Harmonic mean.

So this question falls in the category of 2.

=> So, average speed = Reciprocal of mean of reciprocals of 40 & 50.

=> Average speed = Reciprocal of mean of 1/40 & 1/50.

=> Average speed = Reciprocal of (1/40 + 1/50)/2 = Reciprocal of (5+4)/400 = 44 4/9 .

-Shalabh
_________________

Learn how eGMATers improved their GMAT scores by 100+ points - Click here

Learn about our newly released Quant Online course here.

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1670
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 17

Kudos [?]: 682 [0], given: 191

Re: A car travels from Town A to Town B at an average speed [#permalink] New post 14 Jan 2015, 00:22
Average(speed) = \frac{{Total (Distance) }}{{ Total (Time)}}

Let the distance between Town A & Town B = 1

Setting up the equation:

Average speed = \frac{1+1}{\frac{1}{40} + \frac{1}{50}} = \frac{400}{9} = 44\frac{4}{9}
_________________

Kindly press "+1 Kudos" to appreciate :)

Re: A car travels from Town A to Town B at an average speed   [#permalink] 14 Jan 2015, 00:22
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic Cars A and B are traveling from Town X to Town Y on the same route at mikemcgarry 4 09 Jan 2015, 14:44
7 Experts publish their posts in the topic A car traveled 75% of the way from town A to town B at an summer101 12 27 Mar 2013, 06:21
14 Experts publish their posts in the topic A certain car traveled twice as many miles from Town A to Town B as it pgmat 13 27 Jan 2011, 15:35
A car traveled 75% of the way from town A to town B by andrehaui 2 26 Apr 2007, 06:11
a car traveled 75% of the way from town A to town B by christoph 2 26 Feb 2005, 08:22
Display posts from previous: Sort by

A car travels from Town A to Town B at an average speed

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.