y varies inversely with twice the value of x. When y = 8, x = 2. Find y when x = 8.

A.2

B.16

C.24

D.32

Question

y varies inversely with twice the value of x. When y = 8, x = 2. Find y when x = 8. 

A.2 

B.16 

C.24 

D.32

anonymous · Answer

Inverse variation
$$y=\frac{k}{x}$$
Plug in your x and y to solve for k.

anonymous · Answer

Remember to replace x with 2x because "twice the value of x"

cwrw238 · Answer

y varies  as 1/2x
means y = k/2x  where k is some constant

anonymous · Answer

i keep getting B.

anonymous · Answer

That's k, you have to plug in the new x to find the new y.

anonymous · Answer

Take that value of k that you got, and put it and the new x=8 into the equation to solve for y.

anonymous · Answer

So 2?

anonymous · Answer

Oh, wait, what did you get for k? k=32, so yes, y = 2 at x=8 because 2=32/16.

anonymous · Answer

Yes, so i guess ill go with A. 2

anonymous · Answer

$$Inverse \space variation: y=\frac{k}{2x}, \space k=32, \space x=8, \space y=\frac{32}{16}.$$