Problema Solution
The number of digital music players sold since January 1, 2001, has grown at an exponential growth rate of 13.1% per month. What is the doubling time for digital music player sales.
Answer provided by our tutors
let doubling time be x years
2P = P e0.131x
0.131x = ln 2 = 0.6931
x = 0.6931/0.131 = 5.2908 years