Question

Y

Answer 1

We need to find two relations, and use them to find the value of y when z = 15.

We will see that the value of y in that case is 4,860.

We know that y  varies inversely with the square of  x, also y  is also proportional to the cube of  z

Then we can write:

y = k/x^2

y = c*z^3

We also know that:

When x = 3, y = 80.

Replacing that in the first equation to find the value of k:

80 = k/3^2

80 = k/9

80*9 = k = 720

We also know that when x = 2, z = 5

From the first relation we have:

y = 720/2^2 = 720/4 = 180

Now we replace this in the equation of y and z:

y = c*z^3

180 = c*5^3

180 = c*125

180/125 = c = 1.44

Now we need to calculate y when z = 15, then we just need to replace z by 15 in the equation for y and z:

y = 1.44*(15)^3 = 4,860.

If you want to learn more, you can read:

brainly.com/question/2548537