Word Problem - Intermediate Algebra

B

becky0307

New member
Joined
Feb 10, 2010
Messages
12
Hello,
I am truly stumped on this one.
Yearly sales of an electronic device S(t), in millions of dollars, t years after 1998 can be estimated by
S(t) = 100 * 6^t
What is the doubling time for the yearly sales?

I'm thinking that doubling is a clue so I need to multiply something by 2, but not sure?

Thanks for you help in advance.
 
Hello, becky0307!

\(\displaystyle S(t) = 100 * 6^t\)

Plug in t = 0...

\(\displaystyle S(t) = 100 * 6^0 = 100 * 1 = 100\)

So now we know that the initial sales was 100 million, therefore double this would be 200 million. From here we can plug in what we know...

\(\displaystyle 200 = 100 * 6^t\)

and then solve for t!

Hope this helps some!
 
so now I would have equation

200=100*6^t I would divide 200 by 100

2=6^t then taking the common logarithms on both sides
log 2=log6^t
log2=t log 6 using the power rule for logarithms

divide log 2/log 6= t

I hope this is the right way?
t= .38 years?
 
That is really good. You can always check yourself by plugging 't' back into your original equation and see if you get 200.


But I think you did great.
 
You must log in or register to reply here.
Top