Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 24 Sep 2009
Posts: 105

Car B starts at point X and moves clockwise around [#permalink]
Show Tags
26 Feb 2012, 21:51
2
This post received KUDOS
27
This post was BOOKMARKED
Question Stats:
46% (02:24) correct 54% (02:39) wrong based on 645 sessions
HideShow timer Statistics
Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)? A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8
Official Answer and Stats are available only to registered users. Register/ Login.



Math Expert
Joined: 02 Sep 2009
Posts: 43830

Re: Car B starts at point X and moves clockwise around... [#permalink]
Show Tags
26 Feb 2012, 22:13
13
This post received KUDOS
Expert's post
6
This post was BOOKMARKED
NYCAnalyst wrote: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8 Step by step analyzes: B speed: \(2\) mph; A speed: \(3\) mph (travelling in the opposite direction); Track distance: \(2*\pi*r=20*\pi\); What distance will cover B in 10h: \(10*2=20\) miles Distance between B and A by the time, A starts to travel: \(20*\pi20\) Time needed for A and B to meet distance between them divided by the relative speed: \(\frac{20*\pi20}{2+3}= \frac{20*\pi20}{5}=4*\pi4\), as they are travelling in opposite directions relative speed would be the sum of their rates; Time needed for A to be 12 miles ahead of B: \(\frac{12}{2+3}=2.4\); So we have three period of times: Time before A started travelling: \(10\) hours; Time for A and B to meet: \(4*\pi4\) hours; Time needed for A to be 12 miles ahead of B: \(2.4\) hours; Total time: \(10+4*\pi4+2.4=4*\pi+8.4\) hours. Answer: B. Also discussed here: ratesonacirculartrack86675.html#p849908Hope it helps.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7942
Location: Pune, India

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
27 Feb 2012, 04:51
6
This post received KUDOS
Expert's post
3
This post was BOOKMARKED
NYCAnalyst wrote: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8 It is a long question stem so make sure you analyze each statement as you read it otherwise you will waste a lot of time rereading the question again and again. Let me tell you how: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ok, car B covers 2 miles every hour moving clockwise. We don't know the track length yet.Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. Car A is faster and covers 3 miles every hour counter clockwise. Since their directions are opposite, their relative speed = 2+3 = 5 mph. We still don't know the track length so we cannot say where car B was when car A started. All we know is that in 10 hrs, car B traveled 20 miles If the radius of the track is 10 miles, Now we know the track length. It is \(2{\pi}r = 2{\pi}*10 = 20{\pi}.\) It is greater than 20 miles that car B covered in 10 hrs so car B had not finished one round. Of the \(20{\pi}\), it had covered 20 miles. for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)? To pass each other for the first time, cars A and B together need to cover the remaining distance on the circle i.e. \(20{\pi}  20\). To create a distance of another 12 miles, they together need to travel 12 miles more away from each other
Time taken = Total distance to be traveled/ Relative Speed Time taken = \((20{\pi}  20 + 12)/5 = (20{\pi}  8)/5 hrs = 4{\pi}  1.6 hrs\) Car B must have been traveling for \(4{\pi}  1.6 + 10 = 4{\pi} + 8.4 hrs\)
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Math Expert
Joined: 02 Sep 2009
Posts: 43830

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
27 Feb 2012, 08:47



Intern
Joined: 28 Feb 2012
Posts: 22
WE: Information Technology (Computer Software)

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
28 Feb 2012, 20:45
NYCAnalyst wrote: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8 My solution  Let us assume they meet at time t. Till that time, Car B will have travelled a distance of 2t (distance = speed *time). Car A will have travelled a distance equal to (t10)*3 by the same logic. So, we have 2t + (t10)*3 = 2 * pi * 10 (at t ) For putting in another 12 miles between them, 2t + (t10)*3 = 2 * pi * 10 + 12 which gives 2t + 3t  30 = 20*pi+12 5t  30 = 20*pi +12 5t = 20*pi + 42 t = 4*pi + 8.4 ( Answer B)  Deepti



Director
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 527
Location: United Kingdom
Concentration: International Business, Strategy
GPA: 2.9
WE: Information Technology (Consulting)

Cars on circular track [#permalink]
Show Tags
03 Mar 2012, 14:18
Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)? A) 4pi – 1.6 B) 4pi + 8.4 C) 4 pi+ 10.4 D) 2 pi – 1.6 E) 2pi – 0.8 This is how I tried solving this, but got stuck after this. The two cars travel around the circumference of a circle, the measure of which is 2 pi r = 2 pi × 10 = 20 pi miles. Car B has already traveled (2 mph)(10 hours) = 20 miles in a clockwise direction by the time Car A starts moving 10 hours later in a counterclockwise direction (and from the same starting point). At Car A’s start time, the additional distance to cover before the cars meet is (20pi – 20) miles. We are interested in the moment when the cars have passed each other and have traveled another 12 miles: (20 pi – 20) + 12 = (20 pi – 8) miles. No idea what to do after this.
_________________
Best Regards, E.
MGMAT 1 > 530 MGMAT 2> 640 MGMAT 3 > 610 GMAT ==> 730



Manager
Joined: 29 Sep 2008
Posts: 139

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Apr 2012, 01:29
i don't know where i am making the mistake ...
Car B has already traveled (2 mph)(10 hours) = 20 miles in a clockwise direction by the time Car A starts moving 10 hours later in a counterclockwise direction (and from the same starting point).
let x distance from Car A starting point the two cars meet
then distance covered by car B=2pi*1020x time taken by car B=(2pi*1020x)/2 distance covered by car A=x time taken by car A=x/3
equating the two, x/3=(2pi*1020x)/2 2x=60*pi603x x=(60*pi60)/5 x=12(pi1) car B has to travel another 12 miles,therefore time taken by car B=(2pi*1020x+12)/2
or (20*pi812*pi+12)/2=4*pi+2



Math Expert
Joined: 02 Sep 2009
Posts: 43830

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Apr 2012, 03:33
mrinal2100 wrote: i don't know where i am making the mistake ...
Car B has already traveled (2 mph)(10 hours) = 20 miles in a clockwise direction by the time Car A starts moving 10 hours later in a counterclockwise direction (and from the same starting point).
let x distance from Car A starting point the two cars meet
then distance covered by car B=2pi*1020x time taken by car B=(2pi*1020x)/2 distance covered by car A=x time taken by car A=x/3
equating the two, x/3=(2pi*1020x)/2 2x=60*pi603x x=(60*pi60)/5 x=12(pi1) car B has to travel another 12 miles,therefore time taken by car B=(2pi*1020x+12)/2
or (20*pi812*pi+12)/2=4*pi+2 What does the red part even mean? If it means the distance between B and A by the time, A starts to travel then we know exactly what it is. It equal to: \(20*\pi20\) ( carbstartsatpointxandmovesclockwisearound128215.html#p1050349).
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 29 Sep 2008
Posts: 139

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Apr 2012, 04:28
i have explained the statement marked in red "let x distance from Car A starting point the two cars meet" by means of diagram.Both the cars meet at the point.Car A travels x mile while car B travels a distance of 2pi*1020x.Since the time taken would be equal,we are equating the equation x/3=(2pi*1020x)/2
Attachments
File comment: diagram
car pblm.docx [65.79 KiB]
Downloaded 89 times



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7942
Location: Pune, India

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Apr 2012, 09:24
mrinal2100 wrote: i don't know where i am making the mistake ...
Car B has already traveled (2 mph)(10 hours) = 20 miles in a clockwise direction by the time Car A starts moving 10 hours later in a counterclockwise direction (and from the same starting point).
let x distance from Car A starting point the two cars meet
then distance covered by car B=2pi*1020x time taken by car B=(2pi*1020x)/2 distance covered by car A=x time taken by car A=x/3
equating the two, x/3=(2pi*1020x)/2 2x=60*pi603x x=(60*pi60)/5 x=12(pi1)
Everything is correct till here. Now, x is the distance traveled by A so time taken = x/3 = 12(pi1)/3 = 4(pi1) Now notice that they have to together put 12 miles distance between them. They are moving in opposite directions so time taken to cover 12 miles together = 12/(2+3) = 2.4 hrs (relative speed concepts) Total time taken = 4(pi1) + 2.4 = 4*pi  1.6 hrs Car B has traveled 10 hrs extra so it must have been traveling for 4*pi  1.6 + 10 = 4*pi + 8.4 hrs car B has to travel another 12 miles,therefore time taken by car B=(2pi*1020x+12)/2
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Manager
Joined: 07 Sep 2011
Posts: 62
Location: United States
Concentration: Strategy, International Business
WE: General Management (Real Estate)

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Apr 2012, 21:32
Hi Karishma,
I have been fan of your logical approach, which I keep applying wherever possible. More so when I am not very comfortable with algebra part of word problems. I am attempting to solve this question based on logic.
I will consider Pi as 3. So the distance round the circle is 20pi or 60 mi approx. Out of this Car B has already traveled 20 mi in 10 hours. Thus we are left with 40 mi to be covered by A and B together but driving in opposite direction @ 3km/hr and 2km/hr respectively. Thus to cover balance distance plus 12km i.e. 52miles, I need 52/5=10.4 hours.
Thus answer is 10hours plus 10.4 hours i.e. 20.4 hours and answer choice B (4pi+8.4) is correct.



Intern
Joined: 03 Aug 2011
Posts: 41

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
13 May 2012, 02:29
I think there is a flaw in this question... moving on a circular track could not be CONSTANT RATE! it has variable velocity So you could not solve the problem with Rate= Distance/ time Formula. Because this formulation is just for straight distances not for circular ones...
_________________
Keep your eyes on the prize: 750



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7942
Location: Pune, India

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
14 May 2012, 07:58
manjeet1972 wrote: Hi Karishma,
I have been fan of your logical approach, which I keep applying wherever possible. More so when I am not very comfortable with algebra part of word problems. I am attempting to solve this question based on logic.
I will consider Pi as 3. So the distance round the circle is 20pi or 60 mi approx. Out of this Car B has already traveled 20 mi in 10 hours. Thus we are left with 40 mi to be covered by A and B together but driving in opposite direction @ 3km/hr and 2km/hr respectively. Thus to cover balance distance plus 12km i.e. 52miles, I need 52/5=10.4 hours.
Thus answer is 10hours plus 10.4 hours i.e. 20.4 hours and answer choice B (4pi+8.4) is correct. Yes, that's absolutely fine. I followed the exact same approach above (but with pi). I hope you understand that the approximation of pi worked because the answer was also in terms of pi. If you had a pure numerical answer, you would not have assumed pi = 3. Here, pi acted like a variable. Say, if you put pi = 10, you will still get the answer (of course you will need to substitute pi = 10 in the options too)
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7942
Location: Pune, India

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
14 May 2012, 08:02
omidsa wrote: I think there is a flaw in this question...
moving on a circular track could not be CONSTANT RATE! it has variable velocity So you could not solve the problem with Rate= Distance/ time Formula. Because this formulation is just for straight distances not for circular ones... Velocity has two components  speed and direction. Velocity is variable here only because of changing direction. Speed = Distance/Time is applicable for circular distances as well since speed is not a vector. GMAT only deals with speed, not with velocity. Constant rate implies a constant speed.
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Director
Joined: 05 Sep 2010
Posts: 829

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
11 Jul 2012, 19:13
"for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them" i have a little problem with the language of the question stem ..isint the question asking that we have to calculate the time of travel since they met for the first time and to the point when the distance between them is 12 miles .in that case the answer wud have been straight 12 /5 hrs . i feel the language is little faulty .karisma ,buneul plz claify



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7942
Location: Pune, India

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
11 Jul 2012, 20:29
aditya8062 wrote: "for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them" i have a little problem with the language of the question stem ..isint the question asking that we have to calculate the time of travel since they met for the first time and to the point when the distance between them is 12 miles .in that case the answer wud have been straight 12 /5 hrs . i feel the language is little faulty .karisma ,buneul plz claify The language of the question isn't very good. This does lead to different interpretations by different people sometimes. But most people will interpret it as 'from the starting point to right now (which is the point when the cars have passed each other for the first time and put another 12 miles between them)' In GMAT, the language is always very clear. e.g. you could be given "After some time, the cars had put a distance of 12 miles between them after meeting for the first time. For how many total hrs did car B travel till this time?"  In this case, your answer is the one given above. or you could have "After meeting for the first time, the cars continued on their respective paths and put a distance of 12 miles between them (they have met only once). How long has car B been traveling since meeting car A for the first time?"  In this case, your answer is 12/5
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Director
Joined: 22 Mar 2011
Posts: 608
WE: Science (Education)

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
11 Jul 2012, 20:50
1
This post received KUDOS
NYCAnalyst wrote: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8 It is easier to understand the question using a drawing: \(A_1\) and \(B_1\) are the points A and B are respectively after their first time pass. If we denote by T the time B travels from X to \(B_1\), then the total distance the two cars travel until the situation depicted in the figure is one whole circumference of the circle plus the overlap of 12 miles. Car A travels \(T10\) hours. We can write the following equation: \(2T+3(T10)=2\pi10+12\) or \(5T=20\pi+42\), from which we get \(T=4\pi+8.4\). Answer: B
Attachments
CircleMotion4GC.jpg [ 12.14 KiB  Viewed 22607 times ]
_________________
PhD in Applied Mathematics Love GMAT Quant questions and running.



Intern
Joined: 11 Jul 2012
Posts: 42

Car B starts at point X and moves clockwise around a circular tr [#permalink]
Show Tags
23 Sep 2012, 00:21
Let rA and rB denote the speeds of A and B, respectively rA = 3mph, rB= 2mph C = 20*π miles (circumference of the circle) In 10h B will have covered 20 miles (10h * 2mph) The remaining distance 20*π  20 miles and an extra 12 miles (20*π 8 ) got to be covered both by A and B with relative speed of 5mph. Thus B will have been racing a total time of 10h + ((20*π 8 )/5) h = 4*π + 8.4 hours Brother Karamazov



Senior Manager
Joined: 13 May 2013
Posts: 456

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
05 Aug 2013, 11:55
Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
This problem deals with the distance the cars have moved over a certain period of time so we should find the distance (circumference) of the track: r=10 c=(pi)d c=(pi)(20) c=20(pi)
Car B leaves 10 hours before car A. When car A starts traveling B has traveled: distance=rate*time: distance=2miles/hour*10 hours: D=20 miles.
We need to know how long it takes for them to reach one another then how long it takes for them to put another to miles between the two of them.
When car A leaves B has already traveled for 10 hours and 20 miles. Therefore, car A and B have [(pi)20  20] miles to travel before they reach one another.
Their combined rate is 2miles/hour and 3miles/hour = 5 miles/hour
Time = distance/rate Time = [(pi)20  20]/5 Time = [(pi)4  4]
It takes [(pi)4  4] hours for them to reach one another.
We now have to figure out how long it takes for them to travel past one another and put 12 miles between them:
Distance = r*t 12 = (2+3)*t 12/5 = time
It takes another 2.4 hours for the two cars to travel a combined 12 hours away from one another.
So, Car B has been on the circuit for 10 hours + (pi)4  4 hours + 2.4 hours: (pi)4+8.4 hours total.
ANSWER: B. 4pi + 8.4



Director
Joined: 10 Mar 2013
Posts: 584
Location: Germany
Concentration: Finance, Entrepreneurship
GPA: 3.88
WE: Information Technology (Consulting)

Re: Car B starts at point X and moves clockwise around [#permalink]
Show Tags
18 Dec 2015, 10:20
NYCAnalyst wrote: Car B starts at point X and moves clockwise around a circular track at a constant rate of 2 mph. Ten hours later, Car A leaves from point X and travels counterclockwise around the same circular track at a constant rate of 3 mph. If the radius of the track is 10 miles, for how many hours will Car B have been traveling when the cars have passed each other for the first time and put another 12 miles between them (measured around the curve of the track)?
A. 4pi – 1.6 B. 4pi + 8.4 C. 4pi + 10.4 D. 2pi – 1.6 E. 2pi – 0.8 Hi Guys, here's my approach. I just don's like using constant Pi here and will replace it with ~ 3 Radius = 10 so the circumference = 20*Pi = 20*3=60 Car B = has already traveled 10 Hours x 2 mph = 20 and Rate A + Rate B = 5. They must travel 40 miles to meet and additional 12 miles as stated in the question = 52 Miles \(5*t=52\) so t=10,4 Hours + 10 hours previously traveled by Car B = 20,4 = 4pi + 8.4 or 4*3+8,4=20,4
_________________
When you’re up, your friends know who you are. When you’re down, you know who your friends are.
Share some Kudos, if my posts help you. Thank you !
800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50 GMAT PREP 670 MGMAT CAT 630 KAPLAN CAT 660




Re: Car B starts at point X and moves clockwise around
[#permalink]
18 Dec 2015, 10:20



Go to page
1 2
Next
[ 21 posts ]



