Question

W varies jointly with x, y, and z. What happens to W when x, y, and z are each doubled?

W is halved.
W is doubled.
W is quadrupled.
W is multiplied by 8.

Answer 1

W is multiplied by 8.

Answer 2

W is multiplied by 8. Option(d)

Explanation:

Given that,

W varies jointly with x, y and z.

It means W is directly proportional to xyz

So,

W ∝ xyz

W = kxyz

where 'k' is constant

Now double the x, y & z

W' = k(2x)(2y)(2z)

W' = k (2*2*2)(xyz)

W' = 8kxyz

W' = 8(W) ∵W = kxyz

So, W is multiply by 8 when x, y, z are double.

That's the final answer.