Question

There are 1300 people over the age over the age of 12 in the small town. If the same rate of cell phone usage continues , how many yrs will it takes for 1300 people have a cell phone.

Answer 1

We have to find how many years it will take for the 1300 people to have a cellphone.

This means we have to find x for f(x) = 1300, that is "the number of people using cellphones at time x is 1300".

Then, we can write:

`\begin{gathered} f(x)=1300 \\ 880(1.03)^x=1300 \\ 1.03^x=(1300)/(880) \\ 1.03^x\approx1.477 \\ x\cdot\ln (1.03)=\ln (1.477) \\ x=(\ln (1.477))/(\ln (1.03)) \\ x\approx(0.39)/(0.03) \\ x\approx13.2 \end{gathered}`

Answer: it will take 13.2 years for the 1300 people to have a cellphone.