Question

If y varies jointly as x and z when x = 5, y = 80, and z = 8. what is y when x = 16 and z = 2?

Answer 1

We are given that y varies jointly as x and z

Mathematically,

`y=kxz`

Where k is the constant of proportionality.

When x = 5, y = 80, and z = 8

`\begin{gathered} y=kxz \\ 80=k\cdot5\cdot8 \\ k=(80)/(5\cdot8) \\ k=2 \end{gathered}`

So, the relationship becomes

`y=2xz`

What is y when x = 16 and z = 2?

`\begin{gathered} y=2xz \\ y=2\cdot16\cdot2 \\ y=64 \end{gathered}`

Therefore, the value of y is 64