college math
posted by Lorie on .
A quantity, W, is directly proportional to X and the square 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 appreciate all the help! :)

if you know what direct and inverse variations are, then you know that
w = kxy^2/z^3
plug in w,x,y,z to get k:
3=k(4)(4)/64
3 = k/16
k=48 so,
w = 48xy^2/z^3
Now plug in the new x,y,z to get w, since we now know k.