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Bottle nosed dolphin question

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bwsailor
 Post subject: Bottle nosed dolphin question
 Post Posted: Wed Sep 24, 2008 6:29 pm 
On average, the bottle-nosed dolphin comes up for air once every two minutes; the beluga whale, a close relative, comes up for air on average once every five minutes. The number of times a bottle-nosed dolphin would come up for air in a 24 hour period is approximately what percent greater than the number of times a beluga whale would come up for air in that same period?

The answer is 150%, but wouldn't that only be the answer if the question was "...what percent OF the number of times a beluga whale would come up for air in that same period." If it asks for the percent that it is greater, wouldn't the more accurate answer be 50%? In one hour the dolphin comes up 30 times and the beluga comes up 20 times. 30 is 50% greater than 20, although it is 150% of 20.

Am I wrong here?

Thanks!
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Guest
 Post subject: 150% i correct
 Post Posted: Thu Sep 25, 2008 8:14 am 
BD 1(once) in 2 min
BW 1(once) in 5 min

BD 1Hr 30 times (60/2) 24 hrs 720 times
BW 1 Hr 12 times (60/5) 24hrs 288 times

BD 432(720-288) times more than BW

432/288 * 100

150 %

even if you do 30/12* 100 it comes upto 250% for BD and its 150% MORE than 100% for BW
so the answer is 150%
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esledge
 Post subject:
 Post Posted: Mon Oct 27, 2008 2:15 pm 
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ManhattanGMAT Staff


Posts: 901
Location: St. Louis, MO
bwsailor, I think your confusion simply arose from a computation error.

Quote:
In one hour the dolphin comes up 30 times and the beluga comes up 20 times.

The beluga comes up 12 times: (60 minutes)(one appearance/5 minutes) = 12.

Thanks to the Guest who pointed that out. By the way, notice that the 24 hour period is irrelevant, except for the fact that it tells us we should use the same period for both the dolphin and beluga. You should save some computation time by not multiplying these numbers by 24.

Essentially, the question is:
30 is what % greater than 12?
30-12=18 is what % of 12?

_________________
Emily Sledge
Instructor
ManhattanGMAT
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