Question

If 18.9 million computers were in use in 1980 and the number is rising by 19% annually, predict the number of computers in use in 2015. Round to the nearest whole number of million.

Subject: exponential growth and decay

Answer 1

Answer: 8329 millions.

Explanation:

The exponential growth equation is modeled as :

`f(x)=A(1+r)^x`, where A is the initial amount, r is rate of increase and x is the time period.

Given: The number of computers used in 1980= 18.9 million

The rate of growth = 19% =0.19

The number of years from 1980 to 2015= 35

Now, the number of computers in use in 2015 is given by :-

`f(35)=18.9(1+0.19)^(35)\\\\\Rightarrow\ f(35)=8329.24147329\approx8329`

Hence, the number of computers in use in 2015= 8329 millions.