NEW HERE? LEARN MORE
closeclose
Last visit was: 24 Apr 2024, 22:08 It is currently 24 Apr 2024, 22:08
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

Barbara walked up and down a 25 meter long corridor. When she walked

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92900
Own Kudos [?]: 618846 [1]
Given Kudos: 81588
Send PM
CAT Tests Forum Quiz Mode
Barbara walked up and down a 25 meter long corridor. When she walked [#permalink] New post   12 May 2021, 06:15
1
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

25% (medium)

Question Stats:

80% (01:29) correct 20% (01:52) wrong based on 75 sessions
Hide Show timer Statistics
Barbara walked up and down a 25 meter long corridor. When she walked one way, she walked at 4 meters per second, and when she walked the other way, her speed was 2 meters per second. What was her average speed in meters per second?


A. \(1 \frac{1}{3}\)

B. \(1 \frac{2}{3}\)

C. \(2 \frac{1}{3}\)

D. \(2 \frac{2}{3}\)

E. 3
ShowHide Answer
Official Answer
D
User avatar
D
Nidzo
Director
Director
Joined: 26 Nov 2019
Posts: 792
Own Kudos [?]: 781 [0]
Given Kudos: 58
Location: South Africa
Send PM
GMAT ToolKit User
Re: Barbara walked up and down a 25 meter long corridor. When she walked [#permalink] New post   12 May 2021, 07:16
Time = Distance/Speed

Time of first trip: 25/4
Time of second trip: 25/2

Total time: 25/4 + 25/2
= 25/4 + 50/4
= 75/4

Total distance: 50

Average speed = total distance/total time
50/(75/4)
= 50*(4/75)
= 200/75
= 2 50/75
= 2 2/3

Answer D
avatar
B
rahulms94
Intern
Intern
Joined: 18 Jul 2020
Posts: 14
Own Kudos [?]: 5 [0]
Given Kudos: 239
Send PM
Re: Barbara walked up and down a 25 meter long corridor. When she walked [#permalink] New post   13 May 2021, 22:54
To calculate the avg speed for round trips, use the below formula:

avg.speed = 2ab/(a+b), where a and b are the respective speeds.

Avg. speed = 2*4*2/(4+2)
=16/6 = 8/3 = 2 2/3
User avatar
L
MathRevolution
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 10161
Own Kudos [?]: 16594 [0]
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Send PM
Re: Barbara walked up and down a 25 meter long corridor. When she walked [#permalink] New post   14 May 2021, 00:22
Expert Reply
As the distance is constant, the average speed will be the harmonic average of given speeds

Average speed: \(\frac{2ab }{a + b} = \frac{2 * 4 * 2 }{ 4 + 2} = \frac{16 }{ 6} = \frac{8}{3}\)

Answer D
User avatar
G
wickedvikram
Manager
Manager
Joined: 08 Jun 2008
Posts: 181
Own Kudos [?]: 101 [0]
Given Kudos: 79
Location: India
Concentration: Finance, General Management
Send PM
GMAT ToolKit User Reviews Badge
Barbara walked up and down a 25 meter long corridor. When she walked [#permalink] New post   11 Apr 2023, 05:35
Bunuel wrote:
Barbara walked up and down a 25 meter long corridor. When she walked one way, she walked at 4 meters per second, and when she walked the other way, her speed was 2 meters per second. What was her average speed in meters per second?


A. \(1 \frac{1}{3}\)

B. \(1 \frac{2}{3}\)

C. \(2 \frac{1}{3}\)

D. \(2 \frac{2}{3}\)

E. 3



Av Speed = Total Distance/ Total Time = (25+25)/(25/4 + 25/2)= 8/3= \(2 \frac{2}{3}\)

D
GMAT Club Bot
gmatclubot
Barbara walked up and down a 25 meter long corridor. When she walked [#permalink]
11 Apr 2023, 05:35
Moderators:
Bunuel
Math Expert
92900 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions