What is the constant of proportionality in the equation y=5/4 x

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

Strawberries cause two hours per pound kate buys 5 pounds he gets 20% off discount on the total cost how much does kate pay for the strawberries

The equation of line wx is y=2x-5. write an equation of a line perpendicular to line wx in slopeintercept form the contains points (-1,-2)