The variable z is directly proportional to x, and inversely proportional to y. When x is 8 and y is 18, z has the value 1.3333333333333. What is the value of z when x= 13, and y= 22

Respuesta :

The variable z is directly proportional to x, and inversely proportional to y.

[tex] z\alpha x [/tex]

and

[tex] z\alpha \frac{1}{y} [/tex]

So, [tex] z\alpha \frac{x}{y} [/tex]

[tex] z=k\frac{x}{y} [/tex]

where, k is the constant of proportionality.

When, x=8 and y=18, z is 1.33.

So, plugging x,y and z in z=k\frac{x}{y} to get the value of k we get,

[tex] 1.33=k\frac{8}{18} [/tex]

To isolate, k let us multiply by 18 on both sides

1.33*18=k[tex] \frac{8*18}{18} [/tex]

23.99=k[tex] \frac{8*1}{1} [/tex]

So, 23.99=8k

To solve for k, let us divide by 8 on both sides

[tex] \frac{23.99}{8}=\frac{8}{8} k [/tex]

2.99=[tex] \frac{1k}{1} [/tex]

k=3

Let us plug k=3, x=13 and y=22 to solve for z

[tex] z=3*\frac{13}{22} [/tex]

z=[tex] \frac{39}{22} [/tex]

z=1.77

Answer: z=1.77

The variable z is directly proportional to x, and inversely proportional to y,where k is the constant of proportionality. When, x=8 and y=18, z is 1.33.

So, plugging x,y and z in z=k\frac{x}{y} to get the value of k we get, To isolate, k let us multiply by 18 on both sides

1.33*18=k

23.99=k

So, 23.99=8k

To solve for k, let us divide by 8 on both sides. Let us plug k=3, x=13 and y=22 to solve for z.

z=1.77

Answer: z=1.77