Suppose that y varies jointly with w and x and inversely with z and y = 360 when w = 8, x = 25 and z = 5. How do you write the equation that models the relationship? Then find y when w = 4, x = 4 and z = 3?

Solution:

Given,

y varies jointly with w and x and inversely with z

y = 360 when w = 8, x = 25 and z = 5.

Thus using the direct variation and indirect variation formulas, we get

Y ∝ wx/z

In equation form,

Y = kwx/z.

360 = k(8)(15)/3

K = 9

So the equation

y = 9wx/z.

When w = 4 ,x = 4, and z = 3,

Y = 9(16)/3

Y = 48

Therefore, the equation is y = kwx/z and y = 48.

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Suppose that y varies jointly with w and x and inversely with z and y = 360 when w = 8, x = 25 and z = 5. How do you write the equation that models the relationship? Then find y when w = 4, x = 4 and z = 3?

Summary:

Suppose that y varies jointly with w and x and inversely with z and y = 360 when w = 8, x = 25 and z = 5. The equation that models the relationship is y=(kwx)/z. When w = 4, x = 4 and z = 3, Y = 48.