SOLUTION: I am working on variations and I am having problems...please help The question is: I varies inversely with the cube of W. If I = 32 when W = 1/2, find I when W = 1/3. I co

Algebra ->  Functions -> SOLUTION: I am working on variations and I am having problems...please help The question is: I varies inversely with the cube of W. If I = 32 when W = 1/2, find I when W = 1/3. I co      Log On


   

Question 172253This question is from textbook
: I am working on variations and I am having problems...please help
The question is:
I varies inversely with the cube of W.
If I = 32 when W = 1/2, find I when W = 1/3.
I come up with 2304 but the book comes up with 108, not sure where I am going wrong. I am using the formula I=K/W^3.
Thanks for your help! This question is from textbook

Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
when two items are inversely related it simply means as one increases the other decreases.
:
inverse relationships take the form of ab=k or a=k/b where a varies inversely with b.
:
so in our problem we have I varies inversely with W%5E3
:
therefore we take the form of I%28W%5E3%29=k or 32%281%2F2%29%5E3=k ork=32%281%2F8%29=4...so k=4:
find I when W is 1/3...you would expect since W is decreasing that I will increase.
:
I(W)=k or I%281%2F3%29%5E3=4 or I%281%2F27%29=4..highlight%28I=4%2827%29=108%29