algebra  exponentials
posted by Nilan on .
My question is how do I know that
N increases by a factor of 2.9 each day. (see below)
Let N(t) be number of bacteria after t days. N(t) = Pa^t for some constants P and a. N(2) = 5400 and N(6)=382,000.
a)before working problem, estimate value of N(5).
b) write down 2 equations for P and a, one when t=2 and one when t=6, and use these two equations to compute a and P. Round to three significant digits.
algebra  please help  drwls, Sunday, November 6, 2011 at 6:41am
(a) N increases by a factor of 2.9 each day. Divide 382,000 by 2.9 for N(5)
(b) 382,000 P*a^6
5400 = P*a^2
70.74  a^4
a = (70.74)^(1/4) = ___
Once you have a, solve for P.

Because, as it shows above a = (70.74)^(1/4)= 2.9
and P*a^n multiples by a each day.