A roadway has a 4% grade intersecting a -7% grade at at station 18+50.00. The grades are connected by an 800 foot vertical curve. A sign is proposed to be installed at Station 15+00.00. The bottom of the sign is 7 feet above the roadway. For drivers heading from Station 40+00 to Station 10 + 00, when will they be able to see the full sign? Assume a driver’s eye is 3 feet above the surface of the roadway.