Posted by Ann on .
I am of need of HELP. I am working on the word problems for AXIA math 117 and I do not understand the first problem. I have listed the information below. I have tried many times and I have not figured this out. My assignment is due tomorrow and I am desperate for help with work shown so I can understand. There is multiple parts and I only copied part of it.
The cost, in millions of dollars, to remove x % of pollution in a lake modeled by the equation C=6,000/2002x^2
What is the cost to remove 20% of the pollutant?
Please help! Thanks!

Axia Math 117 
Reiny,
First of all, I don't think you meant to type the equation as you did, or else why not reduce it to
C = 3000  2x^2
So I will assume you meant
C = 6000/(2002x^2)
Secondly, the way you defined x % , we would have to replace x with 20, and then your result would be
C = 6000/(200  800) which will result in a negative cost, thus making no sense.
If we replace 20% with 0.2, we would get
C = 6000/(200  .08) = 30.012
but the cost of removing 90% would then be
6000/(200  1.62) = 30.24
which is only slightly higher than removing 20%.
This does not make sense to me, so please check the typing of the equation, and the definition of x