solving Rational Equations

Question

Suppose that z varies jointly with x and y.

Find the constant of proportionality k if z = 25.2 when y = 2 and x = 7.
k =
Using the k from above write the variation equation in terms of x and y.
z =
Using the k from above find z given that y = 4 and x = 16.
z =

Answer 1

z = kxy

25.2 = k(7)(2)

25.2 = 14k

1.8 = k

 

z = (1.8)(16)(4)

z = 115.2