Question

Supposed y varies jointly with x and z. If y=20 when x=2 and z =5, find y when x=14 and z=8

Answer 1

Given:

The variable, y varies jointly with x and z.

It is given that, y = 20 when x = 2 and z = 5.

To find: Find y when x = 14 and z = 8

Explanation:

Since the variable y varies jointly with x and z.

So let us frame the equation as follows,

$y=\text{kxz}\ldots\ldots\ldots\ldots\ldots(1)$

Substituting y = 20, x = 2 and z = 5 in the above equation. We get,

$\begin{gathered} 20=k(2)(5) \\ 20=10k \\ k=2 \end{gathered}$

Substitute k = 2, x = 14, and z = 8 in equation (1), we get

$\begin{gathered} y=(2)(14)(8) \\ y=224 \end{gathered}$

Final answer: The value of y is 224.