Question

The variable Z is directly proportional to X. When X is 3, Z has the value 54. Wha is the value of Z when X= 12

Answer 1

The variable Z is directly proportional to X
Z = kX (Where k is the constant of proportionality)
To find k
54 = k3
 
k = 54/3
k = 18
 

now find new Z

 Z = 18X
Z = 18(12)
Z = 216