Answer:
B
Step-by-step explanation:
Given y and x vary directly then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 27 when x = 4 , then
27 = 4k ( divide both sides by 4 )
[tex]\frac{27}{4}[/tex] = 6.75 = k
y = 6.75x ← equation of variation
When x = 12 , then
y = 6.75 × 12 = 81
