A $400$ ft$.$ equal tangent crest vertical curve has a BVC station of $100+00$ at $59$ ft elevation.

The initial grade is $2\mathrm{.}0$ percent and the final grade is $-4\mathrm{.}5$ percent.

a$.$ Determine the r $=$ rate of change of grade.

b$.$ Determine the elevation and stationing of PVI, EVC.

c$.$ Determine the elevation and stationing of the high point of the curve.

d$.$ Determine the station numbers, the offset from the curve and the elevations of the midpoint

and the quarter points.

e$.$ Find the passing sight distance if the Lmin is estimated to be $400$ ft$.$