The variables \(x\) and \(y\) vary directly. Which of the following equations could represent the relationship between \(x\) and \(y\)?

W) (\(1/x=1/y\) [one fifth x equals 1 over y]

X) \(x/y=1/5\) [x over y equals one fifth]

Y) \(xy=1/5\) [x y equals one fifth]

Z) \(xy=5\)
X) \(x/y=1/5\)