Answer:
Joint variation says that:
If x varies jointly with y and z i.e,
\(x \propto yz\) then the equation is in the form of
\(x = k (yz)\), where, k is the constant of variation.
As per the statement:
if e varies jointly with f and g
then by definition we have;
\(e = k \cdot fg\) ......[1]
To solve for k:
When e = 4, f = 2 and g = 8
Substitute these in [1] we have;
\(4 = k \cdot 2 \cdot 8\)
⇒\(4 = 16k\)
Divide both sides by 16 we have;
\(\frac{1}{4} = k\)
or
\(k = \frac{1}{4}\)=0.25
Therefore, the constant of variation is, \(\frac{1}{4}\) or 0.25.
