Questions about the world of GMAT Math from other sources and general math related questions.
allenwong2288
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Exponential growth

by allenwong2288 Wed Oct 12, 2011 4:17 pm

I'm currently studying guide 3, the equations inequalities book. On pg 173, #10 the question says

A strain of bacteria multiplies such that the ratio of its population in any two consecutive minutes is constant.

Would someone clarify what this means for me? Does this mean it grows every 2 minutes? What information is it telling you about 2 minutes?

Thanks
Allen
mahajanakhil1985
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Re: Exponential growth

by mahajanakhil1985 Thu Oct 13, 2011 11:39 am

At the end of 1st minute, suppose population is 3.
End of 2nd minute, it is 6.
End of 3rd minute, it is 12.
End of 4th minute, it is 24.
End of 5th minute, it is 48.

As per statement, 3:6=6:12:12:24=24:48

I think that this is what the question says.
allenwong2288
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Re: Exponential growth

by allenwong2288 Thu Oct 13, 2011 5:43 pm

I see. Thanks very much.
abhishek-dutta
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Re: Exponential growth

by abhishek-dutta Tue Oct 18, 2011 1:13 pm

allenwong2288 Wrote:I'm currently studying guide 3, the equations inequalities book. On pg 173, #10 the question says

A strain of bacteria multiplies such that the ratio of its population in any two consecutive minutes is constant.

Would someone clarify what this means for me? Does this mean it grows every 2 minutes? What information is it telling you about 2 minutes?

Thanks
Allen


Min 1 - Population is x

Min 3 - Population is ax

Min 5 - Population is a^2x
tim
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Re: Exponential growth

by tim Wed Nov 23, 2011 1:31 pm

Thanks Abhishek. The idea is that every minute the population is multiplying bu a constant (although not necessarily doubling). This is code for exponential growth, so you need to solve the problem using the techniques you would from exponential growth..
Tim Sanders
Manhattan GMAT Instructor

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