Answer:
k = 3
Step-by-step explanation:
Given that b varies jointly with c and d and inversely with f then the equation relating them is
b = [tex]\frac{kcd}{f}[/tex] ← k is the constant of variation
To find k use the condition c = 4, d = 9, f = 6 , b = 18, then
18 = [tex]\frac{k(4)(9)}{6}[/tex] = [tex]\frac{36k}{6}[/tex] = 6k ( divide both sides by 6 )
3 = k
