Answer:
F = 40
Step-by-step explanation:
Given that F is directly proportional to a then the equation relating them is
F = ka ← k is the constant of variation
To find k use the condition F = 25 when a = 5, then
25 = 5k ( divide both sides by 5 )
5 = k
F = 5a ← equation of proportion
When a = 8, then
F = 5 × 8 = 40
