The exponential model, the predicted sales of portable MP3 players in 2009 are approximately $11.3 billion.
We can use the given information to fit an exponential function to the sales data. Then, we can use that function to predict sales in 2009.
Here's how we can do it:
Let's assume that the sales of MP3 players can be modeled by an exponential function of the form S(t) = a * b^t, where S(t) is the sales in year t, a is the initial sales, and b is the growth factor.
We can use the given data to estimate the values of a and b. For example, we know that S(2000) = 0.09 and S(2005) = 1.17.
Plugging these values into the equation, we get:
0.09 = a * b^2000
1.17 = a * b^2005
We can divide the second equation by the first equation to get rid of a. This gives us:
13 = b^5
Solving for b, we get b ≈ 1.41.
Now we can plug the value of b back into the equation for S(t) to get the prediction for sales in 2009. S(2009) = a * b^2009 ≈ 4.04 * 1.41^9 ≈ $11.3 billion.
Therefore, based on the exponential model, the predicted sales of portable MP3 players in 2009 are approximately $11.3 billion.