Given data:
The given rate deceasing per month is r=5% =0.05.
The initial value of pollution is P=360 parts per million(ppm).
The given time is n=1 month.
(a)
The expression pollution level is,
[tex]P_f=P(1-r)^n[/tex]Substitute the given values in the above expression.
[tex]\begin{gathered} P_f=(360ppm)(1-0.05)^1 \\ =342\text{ ppm} \end{gathered}[/tex]Thus, the final value of pollution after one month is 342 ppm.
(b)
Given data:
The given value of time is n=2.
Substitute given values in the expression for the pollution level.
[tex]\begin{gathered} P_f=(360ppm)(1-0.05)^2 \\ =324.9\text{ ppm} \end{gathered}[/tex]Thus, the final value of pollution after two months is 324.9 ppm.
