Z varies directly as x and y, z = 6 when x=2 and y = 6. Find the value of z when x = 3 and y = 8

12

Step-by-step explanation:

 This is a joint variation problem:

              z varies directly as x and y

Interpreting this;

                z ∝ xy

 Therefore;

               z  = kxy

 z = 6, x = 2, y  = 6

   Now find k,

             6  = 2 x 6 x k

              6  = 12k

               k  =

To find the value of z;

   x  = 3, y  = 8

              z  =    x 3 x 8  = 12

the value of x is 28.2