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

It is currently 15 Sep 2014, 21:13

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

Help with time and distance questions please!!

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Intern
Intern
avatar
Joined: 14 Mar 2013
Posts: 7
Followers: 0

Kudos [?]: 3 [1] , given: 3

Help with time and distance questions please!! [#permalink] New post 02 May 2013, 07:57
1
This post received
KUDOS
1. Bob enters a lift on the 21st floor, which is going up @ 57 floors/min. At the same time Jane enters another lift on the 61st floor which is going down at 63 floors/min. At what floor will they be together?
2. Train A can travel from X to Y, a distance of 100 miles, in 3hrs while train B can travel the same distance in 5hrs. If A starts from X to Y at the same time as B starts from Y to X, then at what distance from X will they meet?


Please help...if possible with explanation...
Intern
Intern
avatar
Joined: 30 Apr 2013
Posts: 22
Followers: 1

Kudos [?]: 1 [0], given: 12

Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 08:40
q1. bob and jane have a combined speed of 120 floors per min ... 2 floors per sec.
total floor diff = 61 - 21 = 40.
total time = 40floors / 2 fl per sec= 20 secs = one third of a minute.
in that time bob goes up 57/3 = 19 floors.
so they meet on floor 40.
1 KUDOS received
Intern
Intern
avatar
Joined: 30 Apr 2013
Posts: 22
Followers: 1

Kudos [?]: 1 [1] , given: 12

Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 08:45
1
This post received
KUDOS
q2. ratio of speeds is 5:3.
so distance will be 5/8 of 100 miles = 62.5 miles from X.
3 KUDOS received
Moderator
Moderator
User avatar
Joined: 02 Jul 2012
Posts: 1228
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 65

Kudos [?]: 679 [3] , given: 116

Premium Member
Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 08:45
3
This post received
KUDOS
aishu4 wrote:
1. Bob enters a lift on the 21st floor, which is going up @ 57 floors/min. At the same time Jane enters another lift on the 61st floor which is going down at 63 floors/min. At what floor will they be together?
2. Train A can travel from X to Y, a distance of 100 miles, in 3hrs while train B can travel the same distance in 5hrs. If A starts from X to Y at the same time as B starts from Y to X, then at what distance from X will they meet?


Please help...if possible with explanation...


1) The distance between Bob and Jane is 40 Floors.

The rate at which they are travelling towards each other is 57 + 63 (Since they are travelling towards each other, I am adding up their rates) = 120 floors/min

Time taken = \frac{40}{120} = \frac{1}{3} mins

So at 120 floors/min, they will cover the 40 floors in a third of a min.

In a third of a min, Bob would have travelled \frac{57}{3} = 19 Floors

So, the floor at which they would meet is 21+19 = 40th Floor

2) The distance between X and Y is 100 miles.

The rate at which they are travelling towards each other is \frac{100}{3} + \frac{100}{5} (Since they are travelling towards each other, I am adding up their rates) = \frac{800}{15} miles/hour

Time taken = \frac{100}{800/15} = \frac{15}{8} hours

So at \frac{800}{15} miles/hour, they will cover the 100 miles in \frac{15}{8} hours

In \frac{15}{8} hours, A would have travelled \frac{100}{3}*\frac{15}{8} = 62.5 miles from X
_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

2 KUDOS received
Intern
Intern
avatar
Joined: 22 Jan 2010
Posts: 25
Location: India
Concentration: Finance, Technology
GPA: 3.5
WE: Programming (Telecommunications)
Followers: 0

Kudos [?]: 12 [2] , given: 3

Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 08:57
2
This post received
KUDOS
1. Bob enters a lift on the 21st floor, which is going up @ 57 floors/min. At the same time Jane enters
another lift on the 61st floor which is going down at 63 floors/min. At what floor will they be together?

Bob and Jane will cover 61 - 21 = 40 floors.
They are moving in opposite directions.So we need to add up their speed to find their relative speed.

They cover 57 + 63 = 120 floors/min.So, they will take 40/120 = 1/3 min.
Now,we need to calculate no of floors anyone has covered in that period.
Bob covers 57/3 = 19 floors.
Hence they will meet at floor = 21+19 = 40.


2. Train A can travel from X to Y, a distance of 100 miles, in 3hrs while train B can travel the same distance
in 5hrs. If A starts from X to Y at the same time as B starts from Y to X, then at what distance from X will they meet?

We'll apply the same logic as above.

Speed of A = 100/3 miles/hr.
Speed of B = 100/5 = 20 miles/hr.

Relative speed of A and B = 20 + 100/3 = 160/3 miles/hr.
Time taken to cover up the distance = (100 * 3 )/160 = 300/160 hrs.
So,the required distance from X = distance travelled by A = 100/3 * 300/160 = 62.5 miles.

---------------------------------------------------------
Please press +1 KUDOS if my post helps you.
Intern
Intern
avatar
Joined: 14 Feb 2013
Posts: 33
Schools: Duke '16
Followers: 0

Kudos [?]: 13 [0], given: 14

Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 11:20
aishu4 wrote:
1. Bob enters a lift on the 21st floor, which is going up @ 57 floors/min. At the same time Jane enters another lift on the 61st floor which is going down at 63 floors/min. At what floor will they be together?


Distance between the two = 61-21 = 40
Speed = 57+63 = 120 / min (As both are coming towards each other) = 120 / 60 sec = 2 / sec

Therefore, time taken = 40/2 = 20 sec = 20/60min = 1/3 min

So, In 1/3 min, bob will be at 21 + (57/3) = 40th floor
same for Jane, 61 - (63/3) = 40th floor
_________________

Consider giving +1 Kudo :) when my post helps you.
Also, Good Questions deserve Kudos..!

Intern
Intern
avatar
Joined: 14 Mar 2013
Posts: 7
Followers: 0

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

Re: Help with time and distance questions please!! [#permalink] New post 02 May 2013, 23:17
Thank you so much, guys!!! :) :)
Re: Help with time and distance questions please!!   [#permalink] 02 May 2013, 23:17
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic Time and Distance question #4 cleetus 2 10 Nov 2010, 07:43
1 Experts publish their posts in the topic Time and Distance question #3 cleetus 1 10 Nov 2010, 07:07
1 Experts publish their posts in the topic Time and Distance question cleetus 4 09 Nov 2010, 12:07
Time and Distance question cleetus 2 09 Nov 2010, 11:27
Probability and Time Distance Question pareekpuneet 8 19 Jul 2009, 18:39
Display posts from previous: Sort by

Help with time and distance questions please!!

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.