Answer:
y = 7.2
Step-by-step explanation:
Given that y varies directly as x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 10 when x = 25, then
10 = 25k ( divide both sides by 25 )
[tex]\frac{10}{25}[/tex] = 0.4 = k
y = 0.4x ← equation of variation
When x = 18, then
y = 0.4 × 18 = 7.2
