A quantity x varies directly with the cube of y and inversely with the square root of z. If x = 457.33333333333 when y = 7 and z = 9, find x when y = 6 and z = 4.

Answer 1

x = ky^3/√z
(x√z)/y^3 = k, a constant.
So, you want x such that
(x√4)/6^3 = (1372/3)(√9)/7^3
...