Car B starts at point X and moves clockwise

[EnriqueR905]

Hello, I can not how to approach this question:


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 counter-clockwise 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)?

4 ^π– 1.6


4 ^π+ 8.4


4 ^π+ 10.4


2 ^π– 1.6


2 ^π– 0.8

correct answer: B

Thank You.

[Sage Pearce-Higgins]

Hi Enrique,

You've come to the right place to ask questions about problems from your practice CAT, but before I help you understand these problems, I need to check a couple of things. I assume that you've checked out the explanations we provide for these problems in the exam review screen. I see that the questions are all taken from your first practice CAT - are you quite new to GMAT? If so, and if you didn't score above 650 in your practice test, then I think that there are more important things for you to do (such as get really good at easy-to-medium level problems) than tackle these problems, which are all in the 700-800 difficulty range (i.e. among the hardest questions we have) and which are related to topics that you'll cover later in the course. Please let me know your thoughts.

[RonPurewal]

Hello, I can not how to approach this question:

hi,
on this forum, it's not acceptable to just post a problem and say "please advise", or "i had no idea how to solve this".

1/
first of all, this is almost certainly not true.
you probably started the problem in some way, and then got stuck at some very specific point(s) along the way.

2/
in the unlikely event that this actually is true—i.e., if you actually looked at this problem and thought, "wow, i have NO idea how to do this at all"—then you're better off leaving the problem and returning to it later.
if we just posted an answer key—which you should have anyway—that wouldn't help you develop your problem-solving skills—and then you'd waste the problem!

so...
please post specifics about the issue(s) you're having with the problem.
what was your approach?
what did you understand?
what didn't you understand?
where did you get stuck?
did you try any alternate approaches?
etc.

thanks.

[EnriqueR905]

Hello Sage, thank you for your response. I am not new to the GMAT and I have already studied all quant guides.

My approach for this question was:

I understand how to place the information required, that the circumference would give me the total distance and the fact that i have to do a rate time distance chart.However, I was not able to interpret the question and how to create a formula based on the information.

[RonPurewal]

in that case, i can't really tell you anything better than "please look at the answer key".

[EricH836]

Hi,

I tried drawing this problem out, but I was not sure how to incorporate the pi sign into my table (e.g., A column, B column, Time column -> from there find the distance that A and B traveled for each 1 hour increment). Is there a way to solve this problem by drawing it out?

Thank you,
Eric

[RonPurewal]

drawing out the situation could certainly help you understand the necessary relationships, yes.

you're not going to mathematically SOLVE the problem just by drawing a diagram -- i.e., you'll still have to make some calculations, using the diagram to help you -- but, the diagram could make the necessary calculations a lot more clear.


__

I was not sure how to incorporate the pi sign into my table

^^ i'm sorry, but i have no idea what you are asking here.