Answer:
[tex]z = \frac{5}{6}[/tex]
Step-by-step explanation:
[tex]z[/tex] ∝ [tex]\frac{k}{w}[/tex]
Where k is a constant we need to find when solving these questions.
[tex]20 = \frac{k}{6}[/tex]
[tex]k = \frac{10}{3}[/tex]
[tex]z = \frac{10/3}{4}[/tex]
[tex]z = \frac{5}{6}[/tex]
