Question

1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by C= 3,000/300-3x.

Please note: x is in percent, not decimal form.

a. What is the cost to remove 75% of the pollutant?

b. What is the cost to remove 90% of the pollutant?

c. What is the cost to remove 99% of the pollutant?

d. For what value is this equation undefined?

e. Do the answers to sections a. through d. match your expectations? Explain why or why not.

Answer 1

for d, when is the denominator zero?

I will be happy to critique your thinking on this. I am uncertain what you are stuck on.

Answer 2

a. C = 3000 / (300 - 3x),
C = 3000 / (300 - 3*75),
C = 3000 / (300 - 225),
C = 3000 / 75 = 40M.

b. Same procedure as a.

c. Same procedure as a.

d. The Eq is undefined when the denominator equals 0:

300 - 3x = 0,
3x = 300,
X = 100%.

So the Eq is undefined when X = 100%.