Question

I BET NO ONE KNOWS THIS y varies jointly as x and z. y=20 when x=2 and z=5 . Find y when x=3 and z=6

Answer 1

Hello!

If y varies jointly with x and z, it'll mean that x and z are being multiplied by a factor "k", to equal y.

To give you a visual, this is what I mean.

That means we'll want to find with the first point we're given:

Which means our equation is:

Now, let's plug in the and from the other point to find .

Explanation:

Answer 2

Hello!

If y varies jointly with x and z, it'll mean that x and z are being multiplied by a factor "k", to equal y.

To give you a visual, this is what I mean.

`y=kxz`

That means we'll want to find
`k` with the first point we're given:
`(2,20,5)`

`20=k(2)(5)`

`20=10k`

`k=2`

Which means our equation is:

`y=2xz`

Now, let's plug in the
`x` and
`z` from the other point to find
`y`.

`y=2(3)(6)`

`y=36`

Hope this helps!