Cellular phones are becoming more popular. The numbers of cellular subscribers are listed in below
![2268_7adc1cbe-31e8-4c18-a48e-c5a25de4c7d1.png](https://secure.tutorsglobe.com/CMSImages/2268_7adc1cbe-31e8-4c18-a48e-c5a25de4c7d1.png)
a. Write a model that relates the millions of subscribers as a function of the number of years since 1983.
b. According to the model, how many subscribers were there in 1995?
c. Use the model to predict when there will be 150 million subscribers