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

It is currently 24 Jul 2014, 13:39

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

IR question _Two Part Analysis

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 05 Dec 2011
Posts: 48
Followers: 0

Kudos [?]: 0 [0], given: 18

IR question _Two Part Analysis [#permalink] New post 02 Jul 2012, 14:58
Image


Please explain me how to solve this one .


Thanks a lot !!
1 KUDOS received
Current Student
User avatar
Affiliations: UWC
Joined: 09 May 2012
Posts: 399
Location: India
GMAT 1: 620 Q42 V33
GMAT 2: 680 Q44 V38
GPA: 3.43
WE: Engineering (Entertainment and Sports)
Followers: 22

Kudos [?]: 193 [1] , given: 100

GMAT Tests User Reviews Badge
Re: IR question _Two Part Analysis [#permalink] New post 02 Jul 2012, 16:50
1
This post received
KUDOS
Known:
Total time 15s
Total Distance: 525m

Then, the average velocity is\frac{525m}{15s} = 35m/s

With a fixed acceleration, we have a evenly spaced set of changing velocity points over time.

Then the average of the velocities is \frac{{V_{15}+V_0}}{{2}}

Thus, what two numbers in the answer choces give us an average of 35m/s?

[Reveal] Spoiler:
\frac{{2+68}}{2} = 35
Intern
Intern
avatar
Joined: 25 Mar 2012
Posts: 34
Followers: 0

Kudos [?]: 0 [0], given: 26

Re: IR question _Two Part Analysis [#permalink] New post 13 Jul 2012, 10:48
macjas wrote:
Known:
Total time 15s
Total Distance: 525m

Then, the average velocity is\frac{525m}{15s} = 35m/s

With a fixed acceleration, we have a evenly spaced set of changing velocity points over time.

Then the average of the velocities is \frac{{V_{15}+V_0}}{{2}}

Thus, what two numbers in the answer choces give us an average of 35m/s?

[Reveal] Spoiler:
\frac{{2+68}}{2} = 35


Can you please explain how the total time is 15seconds? My question might be dumb but i don quite get it. I thought till V15 time was 15 seconds.. After the 15th second with a distance 525 how can we understand that the average time is 15seconds?

Please explain..
1 KUDOS received
Current Student
User avatar
Affiliations: UWC
Joined: 09 May 2012
Posts: 399
Location: India
GMAT 1: 620 Q42 V33
GMAT 2: 680 Q44 V38
GPA: 3.43
WE: Engineering (Entertainment and Sports)
Followers: 22

Kudos [?]: 193 [1] , given: 100

GMAT Tests User Reviews Badge
Re: IR question _Two Part Analysis [#permalink] New post 26 Jul 2012, 02:00
1
This post received
KUDOS
Hi Desperate123, I'm afraid I don't quite understand what you mean?

If you like, you could remove the word total and just focus on the time taken to travel 525m which would give us 35m/s. That is, 35m/s is the average velocity of the plane when it covered 525m. The graph of velocity vs time (for constant accleration) looks something like this:

Attachment:
Capture.JPG
Capture.JPG [ 16.75 KiB | Viewed 1305 times ]


So if the average velocity is 35. Then 35 will be the midpoint of the line and the y-axis end points will be t=0 and t=15. The question requires us to find the x-axis coordinates of the endpoints.
Expert Post
GMAT Pill Instructor
User avatar
Joined: 14 Apr 2009
Posts: 1496
Location: New York, NY
Followers: 278

Kudos [?]: 612 [0], given: 5

Re: IR question _Two Part Analysis [#permalink] New post 27 Jul 2012, 08:28
Expert's post
The source for this question is from GMATPill.

http://www.gmatpill.com/gmat-practice-t ... stion/1150

This question makes use of the distance-rate-time formula.

The acceleration is constant, so we know the velocity goes from a starting speed to a final speed. The one variable we do know is distance.

Distance = rate x time

We know distance AND time.

It's just that the rate is changing - but it's changing at a constant rate of acceleration. Because of that we know there is an average speed. You can rewrite the equation as:

Distance = Avg speed x Time

Avg Speed = Distance / Time
= 525 m / 15s
= 35 m/s

OK, so that is the average speed. But we have to find the starting and final speed. OK...well the average of the starting and final speed will get us the average speed.

So, adding ("starting speed" + "final speed" ) / 2 = 35 m/s

So, "starting speed" + "final speed" = 70m/s

The only 2 possible answer choices whose sum is equal to 70m/s is 2m/s and 68m/s
_________________


... and more


Image What's Inside GMAT Pill?

Zeke Lee, GMAT Pill Study Method (Study Less. Score More.)


GMAT Pill Reviews | GMAT PILL Free Practice Test

Manager
Manager
avatar
Joined: 27 May 2010
Posts: 203
Followers: 2

Kudos [?]: 12 [0], given: 3

GMAT Tests User
Re: IR question _Two Part Analysis [#permalink] New post 28 Jul 2012, 02:31
A little confused with the Question. So are they saying that the plane has traveled 525 m in 15 sec including the initial Vo?
Intern
Intern
avatar
Joined: 31 Jul 2012
Posts: 2
GMAT 1: 740 Q48 V42
Followers: 0

Kudos [?]: 5 [0], given: 1

Re: IR question _Two Part Analysis [#permalink] New post 04 Aug 2012, 11:51
qweert wrote:
A little confused with the Question. So are they saying that the plane has traveled 525 m in 15 sec including the initial Vo?


they don't consider the part where the plane is taxing. The 15 sec and 525m start at the point where it starts accelerating. So in 15 sec its speed goes from v0 to v15 as it covers 525m.

I agree with you that the problem is extremely confusing because it doesn't say when the 15 sec and 525m begin. I'm not convinced it's a valid gmat problem.
Re: IR question _Two Part Analysis   [#permalink] 04 Aug 2012, 11:51
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic Two-Part Analysis herbertvl 2 05 Nov 2013, 01:31
Experts publish their posts in the topic IR Question - Question Type: Two Part Analysis avi2crackgmat 2 03 Mar 2013, 15:07
1 Experts publish their posts in the topic Two Part Analysis - Combinatorics Question macjas 10 25 Aug 2012, 07:18
3 Experts publish their posts in the topic IR Question_table analysis debabrata44 5 03 Jul 2012, 20:12
Analysis of Issues with two parts navdeepbajwa 1 20 Nov 2009, 05:49
Display posts from previous: Sort by

IR question _Two Part Analysis

  Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: Bunuel, WoundedTiger



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®.