Last visit was: 26 Apr 2024, 04:05 It is currently 26 Apr 2024, 04:05

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
SORT BY:
Date
Tags:
Show Tags
Hide Tags
avatar
Intern
Intern
Joined: 05 Feb 2011
Posts: 8
Own Kudos [?]: 56 [47]
Given Kudos: 0
Send PM
Most Helpful Reply
avatar
Manager
Manager
Joined: 09 Aug 2010
Posts: 52
Own Kudos [?]: 140 [38]
Given Kudos: 7
Send PM
Tutor
Joined: 16 Oct 2010
Posts: 14824
Own Kudos [?]: 64929 [26]
Given Kudos: 426
Location: Pune, India
Send PM
General Discussion
Manhattan Prep Instructor
Joined: 04 Dec 2015
Posts: 935
Own Kudos [?]: 1541 [1]
Given Kudos: 115
GMAT 1: 790 Q51 V49
GRE 1: Q170 V170
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
1
Kudos
Expert Reply
primmadona wrote:
Hi All,
I found this word question on distance- speed- time which I was able to solve quickly by using algebra, but somehow I cannot solve it by using only logic and arithmetic. I will really appreciate if you can help with detailed approach of how to solve this problem using only logic and arithmetic (not algebra)

Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?
60
72
84
90
120

Thank you,
Dona


Nice question. It's always worth trying to figure out a simpler way of approaching a problem.

I typically do these by creating a chart. One column of the chart is 'time'. The other columns tell me where each person in the problem is located at that time.

In this problem, it would look like this. I started counting up in 12-minute intervals, because all of the answer choices are multiples of 12. 12 minutes is 0.2 hours. In 0.2 hours, Tom will travel 1.2 miles and Linda will travel 0.4 miles.

0 hours:
Tom: 0, Linda: 0

1 hour:
Tom: 0, Linda: 2

1.2 hours:
Tom: 1.2
Linda: 2 + 0.4 = 2.4

1.4 hours:
Tom: 1.2 + 1.2 = 2.4
Linda: 2.4 + 0.4 = 2.8

1.6 hours:
Tom: 2.4 + 1.2 = 3.6
Linda: 2.8 + 0.4 = 3.2

1.8 hours:
Tom: 3.6 + 1.2 = 4.8
Linda: 3.2 + 0.4 = 3.6

2.0 hours:
Tom: 4.8 + 1.2 = 6.0
Linda: 3.6 + 0.4 = 4.0

2.2 hours:
Tom: 6.0 + 1.2 = 7.2
Linda: 4.0 + 0.4 = 4.4

2.4 hours:
Tom: 7.2 + 1.2 = 8.4
Linda: 4.4 + 0.4 = 4.8

2.6 hours:
Tom: 8.4 + 1.2 = 9.6
Linda: 4.8 + 0.4 = 5.2

2.8 hours:
Tom: 9.6 + 1.2 = 10.8
Linda: 5.2 + 0.4 = 5.6

3.0 hours:
Tom: 10.8 + 1.2 = 12.0
Linda: 5.6 + 0.4 = 6.0

Unfortunately this didn't give us an exact answer, but it's close enough that we can estimate. Tom and Linda covered the same distance at about 1.5 hours. Tom covered twice Linda's distance in exactly 3 hours. The difference is 3-1.5 = 1.5 hours, which is 90 minutes.
Current Student
Joined: 18 Jun 2016
Posts: 221
Own Kudos [?]: 613 [4]
Given Kudos: 111
Location: United States (NY)
GMAT 1: 720 Q50 V38
GMAT 2: 750 Q49 V42
GPA: 4
WE:General Management (Other)
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
3
Kudos
1
Bookmarks
primmadona wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A. 60
B. 72
C. 84
D. 90
E. 120

Hi All,
I found this word question on distance- speed- time which I was able to solve quickly by using algebra, but somehow I cannot solve it by using only logic and arithmetic. I will really appreciate if you can help with detailed approach of how to solve this problem using only logic and arithmetic (not algebra)

Thank you,
Dona

Here is the logical way to solve this..

Speed of Tom = 6 mph
Speed of Linda = 2 mph

Relative speed of Tom = 6-2 = 4 mph.

So Compared with Linda, Tom will cover 4 additional miles per hour.

Linda has a head start of 1 hour in which she has covered 2 miles.

Time taken by Tom to cover the same distance as Linda =\(\frac{(Lead Taken by Linda)}{(Relative Speed of Tom} = \frac{2}{4} = \frac{1}{2} = 30 Minutes\)

So, 30 Minutes after Tom started, he will have traveled the same distance as that by Linda, which is 3 miles.

Now, Following are the distances covered by Tom and Linda Henceforth.. (Back Solving..)

1 hour after they have traveled the same distance..

Distance by Tom = 3 + 6 = 9 miles
Distance by Linda = 3 + 2 = 5 miles.

Option A is out.
120 minutes is too large. E is out.

Lets Put in C as it will help us solve the question fastest now.

After 1 hour, distances stand at

Distance by Tom = 3 + 6 = 9 miles
Distance by Linda = 3 + 2 = 5 miles.

So, after 84 minutes = 60 + 24 minutes,

Distance by Tom = 9 + 2.4 = 11.4 miles
Distance by Linda = 5 + 0.8 = 5.8 miles.

5.8 * 2 = 11.6 - 11.4 = 0.2

C is out and since Tom hasn't covered twice the distance so far, D is answer.



Edit: Fixed the grammar

Originally posted by umg on 10 Jul 2017, 02:55.
Last edited by umg on 21 Jul 2017, 03:28, edited 1 time in total.
User avatar
Intern
Intern
Joined: 24 Jun 2017
Posts: 12
Own Kudos [?]: 3 [2]
Given Kudos: 0
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
1
Kudos
1
Bookmarks
1.
2+2x=6x
X=0.5
60(0.5+1)=90
2.
6x=2(2+2x)
X=2
60(2+1)=180
3.
180-90=90
So the answer is c
I am wondering why you use such a complex method
GMAT Club Legend
GMAT Club Legend
Joined: 18 Aug 2017
Status:You learn more from failure than from success.
Posts: 8020
Own Kudos [?]: 4098 [1]
Given Kudos: 242
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1:
545 Q79 V79 DI73
GPA: 4
WE:Marketing (Energy and Utilities)
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
1
Kudos
distance covered in 1st hour by both Linda and Tom
6t= 2(t+1)
t = 1/2 ; 30 mins
and time taken by Tom to cover twice distance covered by Linda
6t= 2*(2t+2)
t = 2 hrs ; 120 mins
∆ ; 120-30 ; 90 mins
option D


HelloKitty wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A. 60
B. 72
C. 84
D. 90
E. 120


Hi All,
I found this word question on distance- speed- time which I was able to solve quickly by using algebra, but somehow I cannot solve it by using only logic and arithmetic. I will really appreciate if you can help with detailed approach of how to solve this problem using only logic and arithmetic (not algebra)

Thank you,
Dona
Current Student
Joined: 03 Jan 2019
Posts: 30
Own Kudos [?]: 27 [0]
Given Kudos: 13
Schools: Ross '23 (A)
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
lawschoolsearcher wrote:
HelloKitty wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A) 60
B) 72
C) 84
D) 90
E) 120


My Solution:
Lrate: 2mph
Trate: 6mph

Ltime: t + 1 hour
Ttime: t hour

Ldistance: 2t + 2
Tdistance: 6t

T to cover L's distance: 2t + 2 = 6t, t = 1/2 hour
T to cover 2L distance: 2 (2t +2) = 6t, 2t = 4, t = 2 hours

2 - 1/2 = 1.5 hours = 90 minutes


hey , everything is fine with the solution just need one clarification Tom started 1 hour late of linds , or you can say linda started one hour early.
so D=S*T ,
1. first solution must be 6*(t+1)=2t
i don't understand why you have added t+1 with respect to lind time ??
GMAT Club Legend
GMAT Club Legend
Joined: 03 Oct 2013
Affiliations: CrackVerbal
Posts: 4946
Own Kudos [?]: 7628 [3]
Given Kudos: 215
Location: India
Send PM
Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
3
Bookmarks
Top Contributor
Case 1: Time taken by Tom to cover the exact distance that Linda has covered

Speed of Linda= 2 miles/hour.
Speed of Tom = 6 miles/hour

Assume that in \(T\) hours , Tom covers the exact same distance that Linda covered.
That means Linda has traveled for\( T + 1\) hours as Tom begins to jog after 1 hour

Distance covered by Tom in T hours = \(6* T\)
Distance covered by Linda in T+ 1 hours = \(2*(T + 1)\)

\(6* T = 2 *(T + 1) \)
\(4*T = 2\)
\(T= 2/4 = 1/2 =.5 hrs\)

we see that in 1.5 hours Linda has covered 2* 1.5 = 3 miles and in 0.5 hours Tom covered the same distance 0.5 * 6 = 3 miles
NOTE: Remember that tom started one hour later.

Case 2: Time taken by Tom to cover twice the distance that Linda has covered.

Assume that in \(T1\) hours , Tom covers twice the distance that Linda covered.

Distance covered by Tom in T1 hours = \(6* T1\)
Distance covered by Linda in T1+1 hours = \(2*(T1 + 1)\)

Since Tom covered twice the distance covered by Linda,
\(6* T1 = 2*(2*(T1 + 1))\)
\(6* T1 = 4* T1 + 4\)
\(2* T1 = 4\)
\(T1= 2 hrs.\)

That means Tom covered 2* 6 = 12 miles in 2 hrs that is double what Linda covered in 3 hours = 2* 3 = 6 miles.

Difference in time taken by Tom in both cases = 2 - .5 = 1.5 hours = 90 mins
Option D is the right answer.

Thanks,
Clifin J Francis,
GMAT SME
Intern
Intern
Joined: 21 Mar 2021
Posts: 26
Own Kudos [?]: 21 [1]
Given Kudos: 26
Send PM
Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
1
Kudos
HelloKitty wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A. 60
B. 72
C. 84
D. 90
E. 120


Hi All,
I found this word question on distance- speed- time which I was able to solve quickly by using algebra, but somehow I cannot solve it by using only logic and arithmetic. I will really appreciate if you can help with detailed approach of how to solve this problem using only logic and arithmetic (not algebra)

Thank you,
Dona


The formula to calculate distance is Distance = (Rate)(Time). So at any given moment Tom's distance (let's call it DT) can be expressed as DT = 6T. So, at any given moment, Linda's distance (let's call it DL) can be expressed as DL = 2(T + 1) (remember, Linda's time is one hour more than Tom's). The question asks us to find the positive difference between the amount of time it takes Tom to cover half of Linda's distance and the time it takes him to cover twice her distance. Let's find each time separately first.

When Tom has covered half of Linda's distance, the following equation will hold: 6T = (2(T + 1))/2. We can solve for T:
6T = (2(T + 1))/2
6T = (2T + 2)/2
6T = T +1
5T = 1
T = 1/5

So it will take Tom 1/5 hours, or 12 minutes, to cover half of Linda's distance. When Tom has covered twice Linda's distance, the following equation will hold: 6T = 2(2(T + 1). We can solve for T:
6T = 2(2(T + 1)
6T = 2(2T + 2)
6T = 4T + 4
2T = 4
T = 2

So it will take Tom 2 hours, or 120 minutes, to cover twice Linda's distance.
We need to find the positive difference between these times: 120 – 12 = 108.

The correct answer is E.
Intern
Intern
Joined: 31 May 2018
Posts: 17
Own Kudos [?]: [0]
Given Kudos: 17
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
Nikhil30 wrote:
lawschoolsearcher wrote:
HelloKitty wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A) 60
B) 72
C) 84
D) 90
E) 120


My Solution:
Lrate: 2mph
Trate: 6mph

Ltime: t + 1 hour
Ttime: t hour

Ldistance: 2t + 2
Tdistance: 6t

T to cover L's distance: 2t + 2 = 6t, t = 1/2 hour
T to cover 2L distance: 2 (2t +2) = 6t, 2t = 4, t = 2 hours

2 - 1/2 = 1.5 hours = 90 minutes


hey , everything is fine with the solution just need one clarification Tom started 1 hour late of linds , or you can say linda started one hour early.
so D=S*T ,
1. first solution must be 6*(t+1)=2t
i don't understand why you have added t+1 with respect to lind time ??









I have the same question
Math Expert
Joined: 02 Sep 2009
Posts: 92929
Own Kudos [?]: 619126 [0]
Given Kudos: 81609
Send PM
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
Expert Reply
Apeksha2101 wrote:
Nikhil30 wrote:
lawschoolsearcher wrote:
Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 6 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover the exact distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?

A) 60
B) 72
C) 84
D) 90
E) 120


My Solution:
Lrate: 2mph
Trate: 6mph

Ltime: t + 1 hour
Ttime: t hour

Ldistance: 2t + 2
Tdistance: 6t

T to cover L's distance: 2t + 2 = 6t, t = 1/2 hour
T to cover 2L distance: 2 (2t +2) = 6t, 2t = 4, t = 2 hours

2 - 1/2 = 1.5 hours = 90 minutes


hey , everything is fine with the solution just need one clarification Tom started 1 hour late of linds , or you can say linda started one hour early.
so D=S*T ,
1. first solution must be 6*(t+1)=2t
i don't understand why you have added t+1 with respect to lind time ??









I have the same question


Linda travels for 1 hour more than Tom. So, if Tom travels for t hours, then Linda travels for t + 1 hours. It's as simple as that!
GMAT Club Bot
Re: Tom and Linda stand at point A. Linda begins to walk in a straight [#permalink]
Moderators:
Math Expert
92929 posts
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne