Question

If x varies jointly as y and z,and x=8 when y=4 and a=9,find z when x=16 and y=6​

Answer 1

Answer:

z=12

Step-by-step explanation:

It is given that x varies jointly as y and z, it means

$x\propto yz$

$x=kyz$

$x(y,z)=kyz$

where, k is the constant of proportionality.

It is given that x=8 when y=4 and z=9

$(8)=k(4)(9)$

$8=36k$

Divide both sides by 36.

$\frac{8}{36}=k$

$\frac{2}{9}=k$

The value of k is 2/9.

$x=\frac{2}{9}yz$

We need to find the value of z when x=16 and y=6​.

Substitute x=16 and y=6 in the above equation.

$16=\frac{2}{9}(6)z$

$16=\frac{4}{3}z$

Multiply both sides by 3.

$48=4z$

Divide both sides by 4.

$12=z$

Therefore, the value of z is 12.