Option C: y = 80x is the right answer
Step-by-step explanation:
Varying directly means that the increase/decrease in one quantity will cause increase/decrease in other quantity.
If y varies directly with x it is given by::
y ∝ x
When the proportionality symbol is removed, a proportionality constant is introduced
y = kx
If x = 1/2 and y = 40
then
[tex]40 = k * \frac{1}{2}\\k = 40*2\\k = 80[/tex]
Putting the value of k, we get
y = 80x
Hence,
Option C: y = 80x is the right answer
Keywords: Proportion
Learn more about proportion at:
#LearnwithBrainly