Answer:
[tex]The\ constant\ of\ variation\ is\ \frac{1}{4}.[/tex]
Step-by-step explanation:
As given in the question
If e varies jointly with f and g.
i.e
[tex]e \propto fg[/tex]
e = kfg
Where k is the constant of variation.
As
When e = 4, f = 2, and g = 8
Put in the above
4 = k × 2 × 8
4 = 16k
[tex]k = \frac{4}{16}[/tex]
[tex]k = \frac{1}{4}[/tex]
[tex]Therefore\ the\ constant\ of\ variation\ is\ \frac{1}{4}.[/tex]