To determine the equation for cyclist one you have to calculate the slope of the line using two points.
The line starts at the origin (0,0) and passes through the point (1,30), using both points and the following formula you can determine its slope:

(x₁,y₁) → (0,0)
(x₂,y₂) → (1,30)

Once you have calculated the slope, you can use the point-slope form to determine the equation

m=30 and (x₁,y₁) = (0,0)

The equation for cyclist 1 is y=30x