Answer:
x = 4
Step-by-step explanation:
Given y varies inversely as x then the equation relating them is
y = [tex]\frac{k}{x}[/tex] ← k is the constant of variation
To find k use the condition y = 8 when x = 10
k = yx = 8 × 10 = 80
y = [tex]\frac{80}{x}[/tex] ← equation of variation
When y = 4, then
4 = [tex]\frac{80}{x}[/tex] ( multiply both sides by x )
4x = 80 ( divide both sides by 4 )
x = 20
