Answer:
y = 7.5
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 20 when x = 8
20 = 8k ( divide both sides by 8 )
2.5 = k
(a)
y = 2.5x ← equation of variation
(b)
When x = 3 , then
y = 2.5 × 3 = 7.5
