Posted by Lorie on .
I really need to know the answer to this extra credit problem. Please help!
A quantity, W, is directly proportional to X and the square of Y and inversely proportional to the cube of Z. W=3 when X=4, Y=2 and Z=4. What is the value of W when X=8, Y=9 and Z=6? Give answer to 3 decimal places.
Thanks in advance. I do not know much about inverse proportions.

College math 
Henry,
W = KXY^2/Z^3 = 3
K4*2^2/4^3 = 3
16K/64 = 3
K/4 = 3
K = 12.
W = KXY^2/z^3 = 12*8*9^2/6^3 = 36.