SOLUTION: If y varies jointly as x and z, and y = 12 when x = 9 and z = 3, find z when y = 6 and x = 15.

Algebra ->  Test -> SOLUTION: If y varies jointly as x and z, and y = 12 when x = 9 and z = 3, find z when y = 6 and x = 15.      Log On


   

Question 799574: If y varies jointly as x and z, and y = 12 when x = 9 and z = 3, find z when y = 6 and x = 15.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If y varies jointly as x and z
y = k*x*z
------
Solve for "k" using "y = 12 when x = 9 and z = 3"
12 = k*9*3
k = 12/27 = 4/9
----
Equation:
y = (4/9)*x*z
---------
Find z when y = 6 and x = 15.
-----
6 = (4/9)*15*z
----
6 = (20/3)z
Ans: z = 18/20 = 9/10
------------------------
Cheers,
Stan H.
======================