Variation Functions

Question

y varies jointly as x and z, and y = 45 when x = 3 and z = 5. Find y when x = 2 and z = 8. Just type the number.

Answer 1

y = kxz = f(x,z) is a function of x and z, with fixed constant k

45 = k(3)(5)

45 = 15k

k=3

y = 3xz = f(x,z)

SO y = f(2,8) = 3(2)(8) = 48