Below question is from Manhattan GMAT book and I am not sure if the answer provided is correct or not.
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.
Please advice how to solve this question.
Thanks in advance!
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Brent@GMATPrepNow
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You transcribed statement 2 incorrectly. It should read as follows:
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.
Of 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
Nee609 wrote: 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.
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.
Of 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
Last edited by Brent@GMATPrepNow on Mon Apr 20, 2015 7:23 pm, edited 1 time in total.
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Matt@VeritasPrep
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Of course, this is a circular track, so even if Berdoff is ahead AND going faster, they'll have to be side by side for a moment again eventually! (That isn't really "catching up", but hey ...)
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I think the term you're looking for is "lapped" 
Cheers,
Brent
Cheers,
Brent
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ceilidh.erickson
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You're right - sometimes things get mixed up on the way to the publisher! This is a known error that we fixed in our 6th edition guides.Nee609 wrote:Exactly, thats what i thought. Manhattan 5th Edition has it wrong. Cool, thanks for clearing that.
If you ever think you've spotted another error, please check out our Errata page for the correction: https://www.manhattanprep.com/gmat/errata/
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Don't you mean 8 mins and not seconds? They question asks the answer in seconds so 60*8= 480 seconds.Brent@GMATPrepNow wrote:You transcribed statement 2 incorrectly. It should read as follows:
Nee609 wrote: 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.
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.
Of 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 seconds to decrease the gap from 200 meters to 0 meters.
In other words, Abernathy will catch up to Berdoff in 8 seconds.
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer = B
Cheers,
Brent
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Brent@GMATPrepNow
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Good catch - I have edited my response accordingly.prada wrote: Don't you mean 8 mins and not seconds? They question asks the answer in seconds so 60*8= 480 seconds.
Cheers,
Brent
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