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When running a mile during a recent track meet...

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When running a mile during a recent track meet...

by swerve » Thu Jan 18, 2018 10:20 am
When running a mile during recent track meet, Nuria was initially credited with a final time of 5 minutes, 44 seconds. Shortly after her run, officials realized that the timing mechanism malfuctioned. The stopwacht did not begin timing her until 11/25 of a minute after she began to run. If the time was otherwise correct, how long did it actually take Nuria to run the mile?

A. 5 minutes, 17.6 seconds.
B. 5 minutes, 21.8 seconds.
C. 5 minutes, 43.56 seconds.
D. 5 minutes, 44.44 seconds.
E. 6 minutes, 10.4 seconds.

The OA is E.

Please, can any expert explain this PS question for me? I can't get the correct answer. I need your help. Thanks.
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by Brent@GMATPrepNow » Thu Jan 18, 2018 10:32 am
swerve wrote:When running a mile during recent track meet, Nuria was initially credited with a final time of 5 minutes, 44 seconds. Shortly after her run, officials realized that the timing mechanism malfunctioned. The stopwatch did not begin timing her until 11/25 of a minute after she began to run. If the time was otherwise correct, how long did it actually take Nuria to run the mile?

A. 5 minutes, 17.6 seconds.
B. 5 minutes, 21.8 seconds.
C. 5 minutes, 43.56 seconds.
D. 5 minutes, 44.44 seconds.
E. 6 minutes, 10.4 seconds.
The long approach is to convert 11/25 of a minute to seconds and then ADD that unaccounted time to Nuria's time (of 5 minutes, 44 seconds)
However, when we check the answer choices before performing any calculations (ALWAYS check the answer choices before performing any calculations), we see that most answers are LESS THAN 5 minutes, 44 seconds

Notice that 11/25 is kind of close to 1/2
So, 11/25 minutes is approximately 1/2 a minute (aka 30 seconds)
When we add 30 seconds to 5 minutes, 44 seconds, we get MORE than 6 minutes.
Answer: E

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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