algebra or mathematics

Question

the variable z is directly proportional to x, and inversely proportional to y. when x is 9 and y is 6, z has the value 19.5. What is the value of z when x=14, and y=11

Answer 1

z=kx/y

19.5=k*9/6=1.5k

k=19.5/1.5=13

z=13*14/11=16.55