Answer:
B = [tex]\frac{4}{9}[/tex]A
Step-by-step explanation:
Given that B varies directly as A then the equation relating them is
B = kA ← k is the constant of variation
To find k use the condition A = 90 and B = 40, then
k = [tex]\frac{B}{A}[/tex] = [tex]\frac{40}{90}[/tex] = [tex]\frac{4}{9}[/tex]
B = [tex]\frac{4}{9}[/tex]A ← equation of variation
