1. A 1400-ft-long sag vertical curve (equal tangent) has a PVC at station 115 + 00 and elevation 750 ft. The initial grade is -3.5% and the final grade is +6.5%. Determine the elevation and stationing of the low point, PVI, and PVT. (5) 2. A 1200-ft equal tangent crest vertical curve is currently designed for 50 mi/h. A civil engineering student contends that 60 mi/h is safe in a van because of a higher driver's eye height. If all other design inputs are standard, how high must the driver's eye height (in the van) be for the student's claim to be valid? (5) 3. An equal-tangent sag vertical curve is designed for 45 mi/h. The low point is 237 ft from the PVC at station 112 + 37 and the final offset at the PVT is 19.355 ft. If the PVC is at station 110+00, what is the elevation difference between the PVT and a point on the curve at station 111 +00?' (5)