Suppose that y varies jointly with w and x and inversely with z and y=400 when w=10, x=25, and z=5. Write the equation that models the relationship.

The equation that models the relationship is:

y = k(w*x/z)

where k is the constant of proportionality. We can find k by substituting the given values into the equation and solving for k:

400 = k(10*25/5)

400 = k(50)

k = 8

Therefore, the equation that models the relationship is:

y = 8(w*x/z)

To write the equation that models the relationship, we need to determine the constant of variation. In this case, y varies jointly with w and x, and inversely with z.

The equation for joint variation is of the form:

y = k * w * x

And the equation for inverse variation is of the form:

y = k / z

To incorporate both joint and inverse variation, we can write the equation as:

y = k * (w * x) / z

Now, we can solve for the constant of variation (k) using the given values: y = 400, w = 10, x = 25, and z = 5.

400 = k * (10 * 25) / 5

To solve for k, we first simplify the equation:

400 = 250k / 5

Next, we multiply both sides of the equation by 5 to eliminate the denominator:

5 * 400 = 250k

2000 = 250k

Finally, we solve for k by dividing both sides of the equation by 250:

k = 2000 / 250

k = 8

Therefore, the equation that models the relationship is:

y = 8 * (w * x) / z