The amount of pollution, A (in part per million), present in the air outside a factory on a recent weekday is represented by the equation A= -t^2+16t+6, where t is the number of hours after 7 AM.

Question

The amount of pollution, A (in part per million), present in the air outside a factory on a recent weekday is represented by the equation A= -t^2+16t+6, where t is the number of hours after 7 AM.
(a) find the Times (in radical form) when there were 42 parts per million of pollution.
(b) use your answer to approximate the Times to the nearest hour.
(c) do you think the pollution level at noon would be higher or lower than 42 parts per million? Explain

Steve · Answer

(a) just solve for t in -t^2 + 16t + 6 = 42 (b) just add that many hours to 7:00 AM (c) pollution at noon is A(5) = 61 So, looks like it is.