Question

Y varies jointly as x and z. y = 36 when x= 3 and z=3. Find y when x=5 and z=2.y=

Answer 1

`\begin{gathered} y\propto x\text{ }* z \\ y\propto xz \\ y\text{ = k}*\text{ xz} \\ k\text{ = }(y)/(xz) \end{gathered}`

Where k is a constant

When y = 36 , x = 3 , z=3

`\begin{gathered} k\text{ = }(y)/(xz) \\ k=\text{ }(36)/(3*3)\text{ =}(36)/(9)\text{ = 4} \end{gathered}`
`\begin{gathered} y\text{ = 4xz} \\ x=\text{ 5 , z = 2} \\ y\text{ = 4 }*5*2=40 \end{gathered}`

The value of y is 40