# math

posted by .

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

• math -

(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.

## Similar Questions

1. ### hard math question

When a certain drug enters the blood stream, its potency decreases exponentially with a half life of 6 hours. Suppose the initial amount of the drug present is A (sub 0). How much of the drug will be present after each number of hours?
2. ### CHEMISTRY

When air pollution is high, ozone (O3) contents can reach 0.60 ppm (ie., .60 mol ozone per million mol air). How many molecules of ozone are present per liter of polluted air if the barometric pressure is 755 mm Hg and the temperature …
3. ### Math

The formula N = 10(4') gives N, the number of bacteria present in a culture after t hours. How many hours does it take for the number of bacteria to grow to 2,560?
4. ### Finance

A company wants to build a new factory for increased capacity. Using the net present value (NPV) method of capital budgeting, determine the proposal’s appropriateness and economic viability with the following information: • Building …
5. ### finance

A company wants to build a new factory for increased capacity. Using the net present value (NPV) method of capital budgeting, determine the proposal’s appropriateness and economic viability with the following information: • Building …
6. ### Calculus

The level of air pollution a distance x miles from a tire factory is given by L(x) = e-0.1x + 1/x2 What is the average level of pollution between 10 and 20 miles from the factory?
7. ### Math

The amount of nitrogen dioxide A in parts per million (ppm) that was present in the air in the city of Homer on a certain day in June is modeled by the function A(t) = -2t^2 + 32t + 12, where t is the number of hours after 6:00 A.M. …