Answer:
c = 48
Step-by-step explanation:
Given c varies directly as a and inversely as b then the equation relating them is
c = [tex]\frac{ka}{b}[/tex] ← k is the constant of variation
To find k use the condition c = 15 when a = 18 and b = 40 , then
15 = [tex]\frac{18k}{40}[/tex] ( multiply both sides by 40 )
600 = 18k ( divide both sides by 18 )
[tex]\frac{600}{18}[/tex] = k
[tex]\frac{100}{3}[/tex] = k
c = [tex]\frac{100a}{3b}[/tex] ← equation of variation
When a = 36 and b = 25 , then
c = [tex]\frac{100(36)}{3(25)}[/tex] = [tex]\frac{3600}{75}[/tex] = 48
