Two racecar drivers, Abernathy and Berdoff, are driving around a

Question

Two racecar drivers, Abernathy and Berdoff, are driving around a circular track. If Abernathy is 200 meters behind Berdoff and both drivers drive at their respective constant rates, how long, in seconds, will it take for Abernathy to catch up to Berdoff?

(1) The circumference of the racetrack is 1,400 meters.
(2) Abernathy is driving 25 meters per minute faster than Berdoff.

Kudos for a correct  solution .

ManojReddy · Answer

Two racecar drivers, Abernathy and Berdoff, are driving around a circular track. If Abernathy is 200 meters behind Berdoff and both drivers drive at their respective constant rates, how long, in seconds, will it take for Abernathy to catch up to Berdoff?

(1) The circumference of the racetrack is 1,400 meters.

This statement is clearly insufficient as we don't know the speeds of the drivers.
 Insufficient

(2) Abernathy is driving 25 meters per minute faster than Berdoff.

let Berdoff speed be x meters/minute, Abernathy speed will be x+25 meters/minute

Abernathy and Berdoff are 200 meters apart, so the time taken for Abernathy to catch up to Berdoff =  \frac{200}{(25+x-x)} = 200/25= 8 minutes
8*60=480 secnds

sufficient

Ans:B

GMATinsight · Answer

Given: Relative Distance between A and B = 200 Meters

Time to catch up = Relative Distance / Relative Speed

So, we require the difference of the speeds of A and B to answer the question.

Statement 1: The circumference of the racetrack is 1,400 meters.

DOesn't provide any information about the  Relative Speed

Hence,   NOT SUFFICIENT

Statement 2: Abernathy is driving 25 meters per minute faster than Berdoff.

i.e. Relative Speed = 25 Meters per Minute
i.e. Time = 200 / 25 = 8 Minutes = 8*60 = 480 Second

Hence,   SUFFICIENT

Answer: Option  B

GMATinsight · Answer

Hi  ManojReddy

Please check the highlighted part which as mistake

Relative Speed = Speed of A - Speed of B

Speed of B = x
Speed of A = x+25

Relative Speed = (x+25)-x = 25 meters per Minute

reto · Answer

Statement 1 is irrelevant. The total racetrack is not needed in order to determine how long it will take for Abernathy to catch up to Berdoff. All we need is the difference in Speed between A and B.
Insufficient.

Statement 2 is sufficient for the above mentioned reason.

Therefore Answer B.

ManojReddy · Answer

It's a miss from my side..
Thanks for correcting.

Regards,
Manoj Reddy

sonalsinha88 · Answer

statement 1: insufficient.

statement 2: speed = distance/time
 
25 =200/t

==> t =8 min = 480 seconds

Sufficient

Answer: B

Vaibhav21 · Answer

Circular race track!
Distance difference/catch-up = 200meters!
St 1 - total circum/distance 1400 meters 
NS
St2 Abernathy is driving 25 meters per minute faster than Berdoff. 
in 1 min 25 meters more than berdoff
in 4 min 100 meters more than berdoff
in 8 min 200 meters more than berdoff
i.e 8x60=480 sec
Suff
Answr B

Bunuel · Answer

MANHATTAN GMAT OFFICIAL SOLUTION:

This question is much easier than most people assume on first glance! It doesn’t matter that the track is circular— if one driver is 200 meters behind another driver and both drive at constant rates, all you need to know in order to determine the time it takes for the rear driver to catch up is the rate at which the rear driver is “gaining” on the front driver.

While of course having the two drivers’ individual rates would be nice, you don’t actually even need that much information— all you need is the rate at which Abernathy is catching up. (When drivers are traveling in the same direction, you subtract their rates; you only need this relative rate.)

Thus, the rephrase is, “What is the difference in the two drivers’ rates?”

(1) INSUFFICIENT: Knowing the length of the track is insufficient and actually pretty useless, since your math problem really ends at the point that Abernathy catches up to Berdoff. Who cares how much track is in front of them when that happens?

(2) SUFFICIENT: This is exactly what you need— if Abernathy is “gaining” at 25 meters per minute, then it will take him 8 minutes to catch up (time = distance/rate, so time = 200/25, which is equal to 8).

The answer is (B).

AjChakravarthy · Answer

Time to catch up is Gap / Difference in Speed
T = 200/diff in speed

State1: Gives the circumference of the track - Not Sufficient

State2:  Is a direct answer. Hence Sufficient.

GMATDemiGod · Answer

I saw this was a bit different then the question I had..

Two racecar drivers, Abernathy and Berdoff, are driving around a circular track. If
Abernathy is 200 meters behind Berdoff and both drivers drive at their respective
constant rates, how long, in seconds, will it take for Abernathy to catch up to Berdoff?
(1) The circumference of the racetrack is 1,400 meters.
(2) Berdoff is driving 25 meters per minute faster than Abernathy.

So

1) Alone NS
2) Alone NS

But C) interesting enough changes the question a bit, since the track is circular it changes the angle and now B is going to lap A and catch up.

The distance between them is now 1200
and the distance is speed in 25

Making B and A together in 2880 seconds?

SO C

IS this right logic?

sushforgmat · Answer

I understand that this is an MGMAT question and there was an error in the second statement which is corrected in the question mentioned in this thread. 
But assuming that there was no error and the question is changed to "how long, in seconds, will it take for Berdoff to catch up to Abernathy?", what would be the ideal way to solve the question?

BrentGMATPrepNow · Answer

Target question :    How long, in seconds, will it take for Abernathy to catch up to Berdoff?

Given : Abernathy is 200 meters behind Berdoff

Statement 1 : The circumference of the racetrack is 1,400 meters.   
The circumference of the racetrack is irrelevant here. What matters is their respective speeds. 
For example, it could be that Abernathy and Berdoff are driving at the same speed, so  Abernathy will NEVER catch up to Berdoff . 
Or it could be the case that Abernathy's speed is 200 meters/second FASTER THAN Berdoff's speed, in which case,  Abernathy will catch up to Berdoff in 1 second . 
Since we cannot answer the  target question  with certainty, statement 1 is NOT SUFFICIENT

Statement 2 : Abernathy is driving 25 meters per minute faster than Berdoff  
If Abernathy is driving 25 meters  per minute  faster than Berdoff, then the GAP between Abernathy and Berdoff will DECREASE by 25 meters EVERY MINUTE. 
There is currently as 200-meter gap 
So, it will take 8 minutes to decrease the gap from 200 meters to 0 meters. 
In other words,  Abernathy will catch up to Berdoff in 8 minutes . 
Since we can answer the  target question  with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent

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