SOLUTION: An environmental group estimates that the amount of pollution in a pond will decrease by 10% each month. To determine the concentration C, of pollutants (in parts per million) afte

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Question 230589: An environmental group estimates that the amount of pollution in a pond will decrease by 10% each month. To determine the concentration C, of pollutants (in parts per million) after (m) months, the group uses the function C(m)=23(0.95)^m
.
(1) to the nearest tenth, what will be the concentration of pollutants in the pond in 5 years?
(2) What was the initial concentration of pollutants in the pond?

Answer by nerdybill(7384) About Me  (Show Source):
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An environmental group estimates that the amount of pollution in a pond will decrease by 10% each month. To determine the concentration C, of pollutants (in parts per million) after (m) months, the group uses the function C(m)=23(0.95)^m
.
(1) to the nearest tenth, what will be the concentration of pollutants in the pond in 5 years?
Since they want the concentration in 5 years but 'm' is in months, we must convert 5 years to months so
m = 5*12 = 60
C(m)=23(0.95)^m
C(60)=23(0.95)^60
C(60)=.9214 parts per million
.
(2) What was the initial concentration of pollutants in the pond?
Here, m=0
C(m)=23(0.95)^m
C(0)=23(0.95)^0
C(0)=23(1)
C(0)=23 parts per million