precalc! help.

Leopard111

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Mar 14, 2010
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The number N of bacteria in a culture is given by the model N=250e^kt where t is the time (in hours). If N=280 when t=10 estimate the time for the population to double in size.

You dont have to find k u must find t without having k? so i do not know how to dot his problem.
 
"Find" Why are you using that word? Try "estimate".

280 isn't much greater than 250. That's kind of a hint.

P.S. Please don't double post.
 
what numbers do i have to plug in though?
is it like this..

280=250e^kt

what number goes in for k since i have to esitmate what t is?
 
You seem to be struggling with the concept of estimation. Do not substitute. Do not "plug in". Estimate. Get it from your head, not from your calculator.

For t = 0, we have N = 250
For t = 10, we have N = 280

Give a go at just saying what it will take to get to 500, given this information.

t = 20 - twice as long?
t = 100 - 10 times as long?

It might help if you have a vision for what an exponential function looks like on a Cartesian Coordinate System.
 
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