If cars F and S are racing on the same circular track and

Question

If cars F and S are racing on the same circular track and each is travelling at a constant rate, for 20 laps around the track, what is the ration of F's rate to S's rate?

1. During F's first 18 laps around the track, F passes S 3 times.
2. F is travelling 3 miles per hour faster than S.

gotoknow3 · Answer

I think st 1 is suff: for every 6 laps F completes, s completes 5;
so 6/5

st 2 not suff

A

vasild · Answer

I think statement (1) is sufficient, assuming that F passes S for the third time at the end of the 18the lap and exactly on the finish line. Then we have:
T = 18/V(F) = 15/V(S), where T=time and V=velocity

Statement (2) would be usable if we had some info about the time it took the cars to finish.

qpoo · Answer

You mean 'ratio' , not 'ration' ?

if os, agree with A

18 and 15 are the number of circles traveled.

Dilshod · Answer

It looks like A,
but what if car F begun racing before car S even started?
There is nothing told, whether the both cars started the race at th same time.

ranga41 · Answer

Statement 1 not sufficient because the cars could have crossed during 

6, 12, 18 or 5, 10, 15

Statement 2 alone obviously not sufficient

I think the answer is E...there are two possible ratios, 6/5 and 5/4...

ranga41 · Answer

Can you post the OE (Official Explanation) please? The answer does not clarify my doubts.

richardj · Answer

No I don't think A is right either.
I think it is E.

Dilshod · Answer

if they both started traveling at the same time, the gaps between #of lapses shouldn't differ.
I think in your case it should be 5, 10, 15. 

In any case, if OA is A, then we should assume that F passed S exactly at the end of 18 and at beginning of 19th lap.

richardj · Answer

You can't assume the OA to solve a problem.

This is a badly worded problem.
I can't believe it would actually be set in a GMAT test.

Priti · Answer

This Q is from a sample paper based practice Qs I had, so there is no OE, but the answer was given as A.

richardj · Answer

Who wrote the sample questions ?

ranga41 · Answer

My bad thanks for noticing, i changed it above...Fortunately the argument still holds good.

If cars F and S are racing on the same circular track and

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